CardIQ Xpress Pro

GE Healthcare

CardIQ Xpress ProCardIQ Xpress Plus

User Guide5180542-100Revision 3

Do not duplicateCopyright 2007by General Electric Company inc. All rights reserved.User Guide

CardIQ Xpress 5180542-100 Rev. 3 i

REGULATORY REQUIREMENTS

This product complies with the regulatory requirements of the following:

• Council Directive 93/42/EEC concerning medical devices: the label affixed to the product testifies compliance to the Directive.

European registered place of business:GE Medical Systems SCSQuality Assurance ManagerBP 34F 78533 BUC CEDEX FranceTel: +33 (0)1 30 70 40 40

• Medical Device Good Manufacturing Practice Manual issued by the FDA (Food and Drug Administration, Department of Health, USA). CardIQ Xpress approved by FDA under k number K041267.

• Underwriters' Laboratories, Inc. (UL), an independent testing laboratory.• Canadian Standards Association (CSA). • International Electrotechnical Commission (IEC), international standards organization, when applicable.• USA/HHS:

United States Federal law restricts this product to use by or on the order of a physician.

• General Electric Medical Systems is ISO 9001 and EN 13485 certified.• The original document is written in English.

CAUTION

CardIQ Xpress 5180542-100 Rev .3 ii

CardIQ Xpress 5180542-100 Rev. 3 iii

TABLE OF CONTENTSREGULATORY REQUIREMENTS .............................................................. ITABLE OF CONTENTS............................................................................ III

CHAPTER 1 - INTRODUCTION .................................................................. 1

1 Introduction ........................................................................................ 22 System Requirements ........................................................................ 23 CardIQ Xpress options ....................................................................... 34 Using CardIQ Xpress .......................................................................... 65 Functions ............................................................................................ 7

Overview ........................................................................................................................................... 7

Vessel Analysis protocols ................................................................................................................. 9

Ejection Fraction ............................................................................................................................. 12

Volume Rendering .......................................................................................................................... 13

Batch ............................................................................................................................................... 14

Using CardIQ Xpress with Multi-phase Datasets ............................................................................ 15

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Other Functions .............................................................................................................................. 16

6 How to use this Document ................................................................ 177 Conventions for this Manual ............................................................ 19

CHAPTER 2 - SAFETY ............................................................................. 21Intended Use .................................................................................................................................. 22

Patient Confidentiality ..................................................................................................................... 22

Volume Viewer 3 ............................................................................................................................. 23

Image Requirements ...................................................................................................................... 23

Vessel Analysis ............................................................................................................................... 23

Views Used with Vessel Analysis ................................................................................................... 25

Tree VR and Angiographic View Images ........................................................................................ 25

Volume Rendering Images ............................................................................................................. 25

Quantification Reload ..................................................................................................................... 26

Phase Registration ......................................................................................................................... 27

Measurements ................................................................................................................................ 28

Annotations on Filmed or Saved Images ........................................................................................ 29

Segmentation .................................................................................................................................. 30

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Segmentation [Pro] ......................................................................................................................... 30

Cardiac Filters ................................................................................................................................. 31

Color Identification [Pro] ................................................................................................................. 31

SOFTWARE SAFETY-RELATED MESSAGES ............................................................................. 32

CHAPTER 3 - SUMMARY OF FUNCTIONS .............................................. 33

1 Multi-Phase Datasets ........................................................................ 342 Vessel Analysis ................................................................................. 353 Ejection Fraction [Pro] ...................................................................... 454 Volume Rendering ............................................................................ 475 Reformat ............................................................................................ 496 Batch ................................................................................................. 507 Phase Registration ........................................................................... 52

CHAPTER 4 - STARTING CARDIQ XPRESS AND LOADING THE EXAM 53

1 Image Requirements ........................................................................ 54

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2 Start CardIQ Xpress .......................................................................... 563 Select Protocol .................................................................................. 57

CHAPTER 5 - VESSEL ANALYSIS - PROCEDURES ............................... 61

1 Overview ........................................................................................... 622 Using the Protocols .......................................................................... 65

Preliminary Step - Automatic Selection ........................................................................................... 67

Overview [Angiographic View] ................................................................................................... 67

Overview [Tree VR] ................................................................................................................... 68

Overview [Left Coronary, Right Coronary, Coronary] ................................................................ 69

Step 1 - Identification of the Vessels to Analyze ............................................................................. 70

Step 2 - Verification/Edition of the Results ..................................................................................... 71

Verify Vessel Identification ......................................................................................................... 73

Verify Centerlines and Cross Sections ...................................................................................... 75

Edit, Register and Save ............................................................................................................. 78

Explore and Analyze .................................................................................................................. 83

Step 3 - Selection of Section of Interest (does not appear for all protocols) ................................... 84

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Overview .................................................................................................................................... 84

Measurements ........................................................................................................................... 85

Step 4 - Add A New Measurement ................................................................................................. 88

Overview .................................................................................................................................... 88

Measurements ........................................................................................................................... 89

Procedure .................................................................................................................................. 89

Step 5 - Reports .............................................................................................................................. 91

CHAPTER 6 - VESSEL ANALYSIS - FEATURES ..................................... 95

1 DYNAMIC AVA .................................................................................. 952 Adding/Removing branches ............................................................ 993 QUICK AVA ...................................................................................... 1014 Stenosis and Aneurysm Tools ....................................................... 1045 Color Identification ......................................................................... 1086 Automatic Measurement points ..................................................... 1127 Minimum/Maximum Length Measurement .................................... 114

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CHAPTER 7 - VESSEL ANALYSIS - VIEWS, CONTROLS, MEASUREMENTS ................................................................................. 115

1 Overview ......................................................................................... 1162 Lumen View .....................................................................................................117

Overview ....................................................................................................................................... 118

Geometry ...................................................................................................................................... 118

Measurements .............................................................................................................................. 119

Graph ............................................................................................................................................ 119

Cursor Line ................................................................................................................................... 120

Active Annotations ........................................................................................................................ 120

On-View Menu .............................................................................................................................. 121

3 Curved View .................................................................................... 122Overview ....................................................................................................................................... 123

Geometry ...................................................................................................................................... 123

Orientation .................................................................................................................................... 125

Measurements .............................................................................................................................. 127


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On-View Menu .............................................................................................................................. 128

4 Oblique View ................................................................................... 129Overview ....................................................................................................................................... 130

Geometry ...................................................................................................................................... 131

Measurements .............................................................................................................................. 131


On-View Menu .............................................................................................................................. 133

5 Other Views ..................................................................................... 1343D View ........................................................................................................................................ 136

6 Density Measurement ..................................................................... 1387 Measurement Accuracy ................................................................. 139

Summary ...................................................................................................................................... 139

Voxel Dimensions ......................................................................................................................... 140

Geometrical Accuracy ................................................................................................................... 141

Acquisition Accuracy ..................................................................................................................... 142

Multi-Phase Measurement Accuracy ............................................................................................ 143

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Quantification Algorithm ................................................................................................................ 143

Partial Volume Effects .................................................................................................................. 144

Display Settings and Display Resolution ...................................................................................... 145

CHAPTER 8 - VESSEL ANALYSIS - CONFIGURING PROTOCOLS ..... 147

1 Pre-defined Protocols .................................................................... 1482 Custom Protocols ........................................................................... 149

Overview ....................................................................................................................................... 149

Configuring Tracking (Vessel Definition) Points ............................................................................ 150

Configuring Reference Points and Measurements ....................................................................... 155

Overview .................................................................................................................................. 155

Configuring Reference Points .................................................................................................. 156

Configuring Measurements ...................................................................................................... 161

Saving the Protocol ....................................................................................................................... 166

Deleting a Protocol ....................................................................................................................... 167

CHAPTER 9 - EJECTION FRACTION [PRO] .......................................... 169

1 Ejection Fraction Protocol ............................................................. 170

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CHAPTER 10 - IMAGE REVIEW ............................................................. 175

1 Volume Rendering Protocols ......................................................... 176"Heart" Protocols ........................................................................................................................... 177

Cardiac Transparency protocol ..................................................................................................... 178

Other Protocols ............................................................................................................................. 180

Volume Rendering ........................................................................................................................ 180

Presets .......................................................................................................................................... 181

Controls ........................................................................................................................................ 182

- VR Presets Panel ................................................................................................................ 183

- VR Opacity Panel ................................................................................................................ 184

- VR Colors Panel .................................................................................................................. 186

- Other Functions ................................................................................................................... 189

2 Cardiac Reformat Batch Protocol .................................................. 190Adjusting Long and Short Axis views ............................................................................................ 191

Using Batch buttons ...................................................................................................................... 192

Using the Double Oblique Protocol ............................................................................................... 198

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3 Phase Registration ......................................................................... 200Overview ....................................................................................................................................... 200

Step 1 - Prepare Registration ....................................................................................................... 201

Step 2 - Phase Registration .......................................................................................................... 202

Step 3 - Saving Results ................................................................................................................ 205

4 Cardiac Specific Review Functions ............................................... 206Layout Presets .............................................................................................................................. 206

3DPOS Active Annotation ............................................................................................................. 208

Cardiac Annotation ....................................................................................................................... 208

Cardiac Filters ............................................................................................................................... 209

Color Identification [Pro only] ........................................................................................................ 210

Color ROI ...................................................................................................................................... 211

Color Ramp ................................................................................................................................... 211

Other Volume Viewer 3 Functions ................................................................................................ 213

CHAPTER 11 - MOVIE CREATION ......................................................... 215

1 Batch Loop ...................................................................................... 216

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CHAPTER 12 - OUTPUT ......................................................................... 217

1 Saving and Filming Images ............................................................ 2182 Filling in a report [Pro] .................................................................... 2193 Annotations .................................................................................... 2234 Save State ........................................................................................ 225APPENDIX 1 - LANDMARK EXAMPLES .............................................. 227

1 Left Coronary Arteries .................................................................... 2282 Right Coronary Arteries ................................................................. 235GLOSSARY ............................................................................................ 241REVISION HISTORY .............................................................................. 247

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CardIQ Xpress 5180542-100 Rev. 3 1

CHAPTER 1 - INTRODUCTION

CardIQ Xpress is an optional software extension of the Volume Viewer 3 application for Advantage Workstation (AW) systems.

It provides you with a number of functions for the analysis and review of CT cardiac exams, in the form of a set of "CardIQ Xpress" protocols available within the AW Volume Viewer 3 application.

The protocols can be used with both single-phase and multi-phase datasets.

CardIQ Xpress comprises four main categories of protocols:-Vessel Analysis protocols for analysis of the coronary vessels,-Ejection Fraction protocol for computation of the left ventricle ejection fraction,-Volume Rendering protocols for global review of the cardiac anatomy,-Batch protocol to prescribe batch series of short and long axis views of the heart.

This manual describes the CardIQ Xpress options. For information concerning the Volume Viewer 3 application, refer to the Volume Viewer 3 user documentation.

This chapter contains the system requirements, an overview of the functions available in CardIQ Xpress, a brief summary of the contents of the manual, and a list of typographical conventions used.

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1 INTRODUCTIONCardIQ Xpress is an optional software extension of the AW Volume Viewer 3 application on Advantage Workstation (AW) systems, in the form of new CardIQ Xpress protocols available within the Volume Viewer 3 application.This manual is a supplement to the Volume Viewer 3 user guide and describes only the use of the CardIQ Xpress option. For all information concerning the use and functions of the Volume Viewer 3 application itself, refer to the Volume Viewer 3 user documentation.

2 SYSTEM REQUIREMENTSThe CardIQ Xpress option can be installed on any AW workstation that already has the AW Basic Display and AW Volume Viewer 3 software installed.

Note: The Volume Viewer 3 application requires an AW workstation equipped with at least 256 Megabytes of memory (RAM), and with AW Basic Display software version AW4.4 or later.

Note: For loading multi-phase datasets a minimum of 1 Gigabyte of memory is highly recommended.

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3 CARDIQ XPRESS OPTIONSCardIQ Xpress has two options: CardIQ Xpress Plus or CardIQ Xpress Pro. Each option includes specific features/protocols as shown in the tables below. Always check these tables to verify their applicability.CardIQ Xpress Plus upgrades CardIQ 2 and allows the review of cardiac images and vessel analysis. CardIQ Xpress Pro offers extra protocols and improved tools to speed up image review and analysis.The intended use in Chapter 2 covers the whole range of clinical features available in CardIQ Xpress Pro. Please note that some of these features are not available in CardIQ Xpress Plus.

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Table 1 - Protocols applicability

CardIQ Xpress protocolsCardIQXpress

Plus

CardIQXpress

ProReformat X XHeart X XHeart Graft X XPhase Registration X XCardiac X XAngiographic View X XCoronary X XLeft Coronary X XRight Coronary X XTreeVR X XCardiac Reformat X XCardiac Transparency XEjection Fraction X

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Table 2 - Features applicability

CardIQ Xpress featuresCardIQXpress

Plus

CardIQXpress

Pro3DPOS Active Annotation X XCardiac filters X XOblique Review X XPhase Drop X XReview Steps X XSave State X XAVA Layouts X XLayout Customization X XColor Identification XReporting X

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4 USING CARDIQ XPRESSThis manual assumes that you are already know how to use the AW workstation, and the AW Basic Display and AW Volume Viewer 3 software.If this is not yet the case, you should first consult the relevant user documentation to familiarize yourself fully with the operation of the workstation, the use of the various controls, menus and windows, and the procedures used for image selection and display, before starting to use CardIQ Xpress.This applies in particular to:• Selecting image series in the AW PatientList for processing with CardIQ Xpress,• Starting CardIQ Xpress or the Volume Viewer 3 application from the AW Patient List,• Using the features other than CardIQ Xpress available in the Volume Viewer 3 application.

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5 FUNCTIONSNote: For protocol applicability, check the table in the CardIQ Xpress options section of Chapter 1.

OverviewCardIQ Xpress consists of a set of protocols for the analysis and review of CT cardiac exams, for both single-phase and multi-phase datasets.The Vessel Analysis protocols (Left Coronary, Right Coronary, Coronary, Tree VR and Angiographic View) allow you to perform a detailed review and quantitative analysis of the coronary vessels. Each protocol contains the successive steps required to perform an analysis: vessel selection, vessel identification and quantification, selection of sections of interest (measurement points), adding quick measurements, report review, and filming or saving of the report. These protocols extract the aorta and coronary vessel tree structure from the surrounding tissue, allowing them to be viewed in isolation.Pre-defined protocols are supplied for the analysis of the left and right coronary artery. Use these as supplied or modify them to create new custom protocols to meet specific requirements. The Ejection Fraction protocol has been developed to provide a simplified workflow for a quick computation of the left ventricle ejection fraction.The Volume Rendering protocols (presets) (Cardiac) allow you to obtain a global view of the cardiac region and to examine overall spatial relationships. Heart, Heart Graft and Cardiac Transparency protocols display VR views of the heart without surrounding anatomy.

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The basic Reformat protocol is the same as that in Volume Viewer 3. The Cardiac Reformat Batch protocol allows you:• to display the volume along the Short Axis, the Long Axis and the Vertical Long axis, and to review the volume,• to prescribe batch series of reformatted images aligned with the short and long axes of the heart, then save

and/or film these as required.

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Vessel Analysis protocols

Left Coronary, Right Coronary and CoronaryLeft Coronary, Right Coronary and Coronary protocols have been developed for rapid, consistent and repeatable quantitative analysis of coronary vessels in cardiac CT data sets.They consist of comprehensive instructions, combined with the tools needed to perform the analysis, contained in protocol panels in the same manner as other protocols in Volume Viewer 3.This minimizes the need to memorize the procedures, or to have to refer continuously to the user documentation.The pre-defined vessel analysis protocols in CardIQ Xpress can either be used directly, or you can modify and edit them to adapt them to your own specific requirements, then save such customized protocols under a new name.CardIQ Xpress is supplied with a set of pre-defined vessel analysis protocols. Use these protocols directly, or modify and edit them to adapt them to your own specific requirements, then save such customized protocols under a new name.

Tree VR and Angiographic ViewTree VR and Angiographic View protocols combine left and right vessel analysis and allow you to review the aorta and the coronary vessel tree structure separate from the surrounding anatomy.These protocols extract and display the aorta, the vessel tree and the cardiac muscles (Angiographic View only) by removing surrounding tissue (bone, lungs, ...) from the 3D volume, allowing them to be viewed in isolation.Tree VR and Angiographic View can be used for plotting points in vessel analysis protocols.

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Functions• The user identifies the branches of the vessel to be analyzed by marking points inside the vessel (start of

section, end of each branch, and intermediate points if required).• The software then automatically detects the vessel centerline for each branch and computes cross section area

and mean diameter at each point.• Using the "Lumen" view together with curved and oblique reformatted views (see next page) the user can now

interactively explore the anatomical context, and if necessary edit the results from the automatic centerline and cross section computation. Computed vessel dimensions (diameter, cross section area) are displayed as a curve in the Lumen view, and the corresponding numerical values can be read at any given point by moving a cursor line.All other Volume Viewer 3 view types are also available during vessel analysis.

• To produce a report, the user marks significant points on the views, such as start and end of an aneurysm or stenosis, position of supplied/supplying vessels, bifurcations, etc. The report will contain both the measurement values concerning these points and a full set of correlated images (curved and oblique views). Automatic measurements computed by the software and manual measurements performed by the user can be included.Once the user has marked the measurement points, the report is generated automatically by the software. Reports can be filmed and/or saved on the workstation.

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By performing the "mechanical" tasks of vessel analysis (centerline detection, quantification, report generation) automatically, CardIQ Vessel Analysis allows you to:

- Analyze cardiac exams rapidly and consistently,- Improve the repeatability of the analysis, in particular between pre and post-surgical exams, but also

between different users,- Produce reports faster, and in a standardized format and style that will help the referring physician to

interpret and use the measurements and images in a consistent manner.

ViewsCardIQ Vessel Analysis uses three specific view types:

- The "Lumen" view shows the complete length of the selected vessel, "unfolded" along the centerline,- The oblique cross section view (X-section) shows a true cross section of the vessel (perpendicular to the

centerline) at any given point,- The oblique longitudinal section view (L-section) shows a longitudinal section of the vessel (parallel to the

centerline) at any given point.CardIQ Vessel Analysis also generates a curved reformatted view that uses the centerline as the reference trace.Oblique X-section and L-section views can be positioned interactively at any point along the centerline using the 3D cursor. The Lumen, oblique L-section and curved views can all be rotated interactively. A "best" oblique L-section can also be displayed that is rotated automatically to show as much of the vessel as possible (plane of maximum curvature).These functions allow you to rapidly and completely explore the anatomical context (lesions, calcifications, branches, nearby anatomy).

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Ejection FractionThe Ejection Fraction protocol has been developped for rapid, consistent and repeatable computation of left ventricle ejection fraction.The Ejection Fraction protocol workflow is structured as follows:• The user checks the consistency of automatic cardiac orientations and ajusts them if necessary,• The user scrolls through the phases to select end systolic and end diastolic phases,• The user places the cursor on the mitral valve using the 4-chamber long axis view for reference, for both

phases,• The software then automatically extracts the left ventricle and removes papillary muscles for both phases. The

user has the ability to adjust and edit the left ventricle segmentation on the 3D view, • The software then automatically computes heart functional parameters such as ejection fraction, stroke volume

and volumes for both phases.

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Volume RenderingCardIQ Xpress is supplied with a set of optimized protocols for cardiac image review (Cardiac, Heart, Heart Graft and Cardiac Transparency).

Use these to obtain a global view of the cardiac region, to examine the overall spatial relations and those parts of the vasculature located on the outside of the region.Volume rendering (VR) is a technique used to display 3D objects by allocating different levels of "opacity" to different voxel values. Additional information can be shown by using color shading.The pre-defined presets supplied with CardIQ Xpress have been optimized to show the large blood volumes and vascular structure as distinct from the surrounding features. You can modify the settings, e.g., to accentuate different features, then save the settings as a new custom preset.CardIQ Volume Rendering protocols with names beginning with "Heart" automatically segment the 3D volume to remove surrounding features (bone, lungs) in order to display only the cardiac regionCardiac Transparency protocol allows you to display a 3D segmented view of the heart cavities and bones. Transparency of each structure can be adjusted separately.

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BatchCardIQ Xpress is supplied with Cardiac Reformat: a Batch protocol allowing you to view, save and film batch series of reformatted images aligned with the short and long axes of the heart.These batch images can be used as input for the Function package. The Cardiac Reformat protocol combines the prescription of batch series of short axis views, four-chamber long axis views and two-chamber long axis views in the same protocol.The Cardiac Reformat protocol replaces former short/long axis batch protocol capabilities.

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Using CardIQ Xpress with Multi-phase DatasetsThe CardIQ Xpress protocols can be used both with single-phase and multi-phase series (with the exception of the Phase Registration protocol which is specific to multi-phase series and of the Cardiac Transparency protocol which is specific to single-phase series).The user selects the series to be processed in the Patient List, then selects the CardIQ Xpress protocol to be used in the Cardiac protocol selection panel. If the selected series is a multi-phase series, a separate panel allows you to select the phases to be loaded.With a multi-phase series, any action taken by the user within a specific phase can be automatically applied to all other phases, by selecting sync mode in the {review controller} (default mode). The protocols allow the user to work within a specific phase and then retrieve the same state for another phase by simply paging through the phases with the Phase active annotation or with the vertical slider of the {review controller} in Card. mode.To apply a given action to only a single phase while multiple phases have been loaded, the user can switch off sync mode, e.g., to individually “clean up” the 3D volumes created with a VR Heart protocol by means of the Scalpel tool, prior to creating a movie loop (beating heart animation).For faster computation and diagnosis, the user is enabled to reduce the number of phases anytime during the study. This “phase drop” procedure is described below:• Click the active phase annotation and click Select Phases in the drop down menu: the phase selection panel

is displayed showing all the currently loaded phases,• Check the boxes of the phases to keep,• Click (Keep selected phases only).

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Note: Unchecked phases cannot be retrieved nor reloaded. Exit out of the application and return to the main browser in order to reload phases.

Other FunctionsCertain separate applications that can be used for cardiac image analysis (such as SmartScore and CardIQ Function) can be invoked directly from the Cardiac category protocol panel.For the use of such applications, refer to their user documentation.

If the CardEP option is also installed on the workstation, a control in the Cardiac category protocol panel allows you to switch directly between the lists of CardIQ Xpress and CardEP protocols. You will note that some of the protocols are common to both options.Refer to the CardEP user documentation for information on the CardEP functions.

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6 HOW TO USE THIS DOCUMENT• For an overview of the features and functions of the CardIQ Xpress software, refer to this chapter.• To review the safety information that you should be familiar with before using CardIQ Xpress, read Chapter 2

- Safety.• For a summary and quick reference guide of the successive operations to be performed when using CardIQ

Vessel Analysis protocols, and of the functions of the Volume Rendering and Batch image review protocols, refer to Chapter 3 - Summary of Functions.

• To start CardIQ Xpress and load an exam, see Chapter 4 - Starting CardIQ Xpress and Loading the Exam.• To familiarize yourself with the procedures (protocol steps) used to process the exam with a CardIQ Vessel

Analysis protocol, refer to Chapter 5 - Vessel Analysis - Procedures.• For a description of the views and controls used with CardIQ Vessel Analysis and for the information required

to assess measurement accuracy, consult Chapter 7 - Vessel Analysis - Views, Controls, Measurements.• To modify existing CardIQ Vessel Analysis protocols and save them as new custom protocols, refer to Chapter

8 - Vessel Analysis - Configuring Protocols.• To familiarize yourself with the CardIQ Ejection Fraction protocol, see Chapter 6 - Ejection Fraction [Pro].• To familiarize yourself with the Volume Rendering and Batch protocols and other available image review

functions, see Chapter 10 - Image Review.• To create Movies and save them, refer to Chapter 11 - Movie Creation.• For notes concerning the saving and filming of the results of CardIQ vessel analysis and image review, refer

to Chapter 12 - Output.• For examples of landmark points that can be used for vessel analysis, see Appendix 1 - Landmark Examples.

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• For a list of the terms in this manual that are specific to the application, refer to the Glossary at the back of the manual.

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7 CONVENTIONS FOR THIS MANUALThroughout the text in this manual, certain type styles and symbols are used to differentiate between one tool or graphic and another:• Applicability appears in bold face italics, within brackets: [CardIQ Xpress Plus, Pro]• Menu and control panel titles appear in bold face: Application menu.• Menu options appear in bold face, within square brackets: [Exit].• Graphical buttons appear in bold face, within parentheses: (View).• On-screen tools appear in bold face, within braces: {scroll bar}.• On-screen prompts and messages appear in italics: Login: .• User typed-in responses appear in bold face italics: sdc.• Keys on the workstation keyboard appear within angle brackets: <Enter>.• A key combination such as <Ctrl-T> indicates holding down the <Ctrl> key, pressing the <T> key, then

releasing the <Ctrl> key.• Mouse buttons are underlined: left.Whenever this manual refers to "clicking", "selecting", "pressing a button", etc. with the mouse, this always means using the left mouse button, unless the middle or right mouse button is specifically mentioned.

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Safety notice legends:THIS INDICATES A POTENTIALLY HAZARDOUS SITUATION WHICH, IF NOT AVOIDED, COULD RESULT IN DEATH OR SERIOUS INJURY.

This indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.

This indicates a non-hazardous situation which, if not avoided, could result in equipment damage, lost time, or reduced image quality.

WARNING

CAUTION

NOTICE

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CHAPTER 2 - SAFETY

To assure an efficient and safe use of CardIQ Xpress, it is essential to read this chapter before attempting to use the package.This chapter is extremely important. It contains safety information that you must thoroughly understand before you begin to use the software.The primary users of CardIQ Xpress software application shall be a CT, MR, nuclear medicine, or radiology technologist, radiologist, cardiologist, or physician qualified with advanced applications training for software competencies or other personnel that the owner feels is properly trained for this software use (radiology assistant, physician assistant, etc...). To avoid usability error, the user MUST have a good knowledge and understanding of both the Advantage Workstation and primary operating function of this software application. This will be accomplished through applications training and through the correct knowledge and application of User Guide content. Please contact your GE representative to order and follow this mandatory training. A qualified individual is determined by the site. The site is the owner of the program and can be located within either hospital, clinic, or private office setting (fixed or mobile) or wherever an AW Workstation, either a fixed or remote, is located. Make certain that the correct version of your operator manuals are readily available at all times. Make a point to review the procedures and safety precautions periodically.Additional safety concerns are addressed in the Advantage Workstation Basic Display and Volume Viewer 3 documentation.

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Intended UseCardIQ Xpress is a CT image analysis software package, which allows the visualization of 2D and 3D medical image data of the heart derived from DICOM 3.0 compliant CT scans for the purpose of cardiovascular disease assessment. It provides functionally for 2D/3D rendering, assessment of calcified and non-calcified plaque to determine the densities of the plaque within a coronary artery, ventricular function of the heart, and measurement tools to detect coronary artery stenosis. This product can be used to help a trained physician to process, render, review, archive, print and visualize cardiac anatomy and coronary vessels.

This tool provides the physician with additional information, meant to complement diagnosis based on classical techniques.

Patient ConfidentialityThe equipment on which the CardIQ Xpress application runs includes one or more hard disk drives which may hold medical data related to patients. Such equipment may in some countries be subject to regulations concerning the processing of personal data and the free circulation of such data. It is strongly recommended that access to patient files be protected from all persons not in medical attendance.

CAUTION

CAUTION

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Volume Viewer 3CardIQ Xpress is a software extension of the Volume Viewer 3 application and uses several of the features of this application. When using CardIQ Xpress, you should be fully familiar with these features and the relevant safety information from the Volume Viewer 3 user documentation.

Image RequirementsIt remains the responsibility of the physician to determine whether the inter-slice distance of a given exam is acceptable for use with CardIQ Xpress.Always bear in mind that, within an exam, details with dimensions in the order of or less than the inter-slice distance cannot be identified with an acceptable degree of reliability.

Vessel AnalysisBefore using an image set for vessel analysis, the user should check for the presence of heart beat motion and other artifacts on axial and coronal images.It is the user's responsibility to insure that sufficiently accurate acquisition parameters are used with respect to the dimensions of the features to be analyzed.Insufficient acquisition resolution (temporal, dimensional and contrast) may result in pathologies or other anatomical features not being visible on the images. It may also result in degraded measurement results and the appearance of artifacts.

The automatic vessel tracking algorithm (vessel identification) relies on the user correctly marking the start and end points of the vessel branches to be tracked.

CAUTION

CAUTION

CAUTION

CAUTION

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Incorrectly marking a "start of section" point inside the aorta rather than inside the coronary ostium (origin) and/or marking an end point at a location that is not a part of the coronary vessel structure to be analyzed may result in the software identifying a part of the cardiac vascular structure completely different from the one intended. It is the responsibility of the user to verify that all vessel branches to be analyzed have been identified correctly by the software. This verification is more reliable when done on a MIP view.

In difficult situations, such as a vessel with a complex trajectory, or vessels touching each other in the images, the automatic vessel tracking algorithm may not always follow the correct trajectory. The user should always examine the computed trajectory before moving on to the next step in the protocol, and if necessary correct the result either by modifying the centerline trace or by correcting the tracking points and/or adding intermediate points, then repeating the centerline detection process.

Correct vessel quantification is critically dependent on factors such as acquisition image quality and voxel size (image resolution and inter-slice distance), and anomalies may occur because of limitations in the available data. It is the responsibility of the user to verify the result of the vessel identification and quantification process before using the data for analysis.

Make sure to deposit the initial point close to the aorta center for dual branch protocols, and close to the ostium for single branch protrocols. Always check the tracking result on a 3D MIP view.

CAUTION

CAUTION

CAUTION

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Views Used with Vessel AnalysisIn the "Lumen" view, the geometrical transformations necessary to "unfold" the vessel, or, in other words, to transform the three-dimensional centerline into a straight line, result in a degree of geometrical distortion of the anatomical features in this view, so that the view does not represent the real orientation or trajectory of the vessel.For these reasons the Lumen view should be used for orientation purposes only, NOT for diagnostics.

Tree VR and Angiographic View ImagesBecause of the limitations in the available data and the different types of image processing used, the Tree VR and Angiographic View images may not clearly show all features of the vascular anatomy (this applies in particular to small and low-contrast features). The Tree VR and Angiographic View images should always be used together with the original acquisition images.

Volume Rendering ImagesOn views displayed in volume rendering mode, the visibility of anatomical features depends on settings of curve type (threshold mode), opacity thresholds and maximum opacity. Essential anatomy or pathologies may not be visible for a given setting of these parameters.Views that use volume rendering should always be correlated with the original acquisition images.

CAUTION

CAUTION

CAUTION

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Volume Rendering protocols with names beginning with "Heart" use an automatic segmentation feature to remove surrounding tissue (bone, lungs) and display only the cardiac region.The user should cross-check on the original acquisition images that no essential anatomy or pathologies have been removed from the Volume Rendering images by this process.

Quantification ReloadReloading a saved tracking result shall restore the tracking centerline in a similar state as when it was saved. The software will then compute the quantification automatically starting from the centerline.

CAUTION

CAUTION

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Phase RegistrationWhen performing a Manual registration, the result of the registration can only be visualized on a small part of the volume (the axial, oblique and coronal views for the current location).

Due to several factors, such as variation in heart movements or the fact that some cardiac regions may be at rest at different phase locations, this operation can result in new misregistration artifacts in other parts of the volume.

Therefore, when using this mode, carefully study the entire volume in all rotations, before saving, networking or filming any images created using phase registration, so as to check that the registration has not degraded image quality.

When performing a registration (in particular, in the Around Cursor mode, or in a Vessel Analysis protocol), the software looks only at the misregistration in a specific region.


Therefore, when using this mode, carefully study the entire volume in all rotations, before saving, networking or filming any images created using phase registration, so as to check that the registration has not degraded image quality.

CAUTION

CAUTION

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MeasurementsThe software calculates and displays measurements with a resolution of one decimal place (such as 0.1 mm, 0.1 degree, etc.).You should be aware that the real measurement accuracy is generally considerably less for a number of different reasons.To assess the accuracy of the measurements performed with CardIQ Xpress, you should be fully familiar with the section "Measurement Accuracy" in the chapter "Measurements" of the Volume Viewer 3 User Guide, and with the information in Chapter 7 - Vessel Analysis - Views, Controls, Measurements, section "Measurement Accuracy", page 139 onwards.

Distance, angle and area measurements are valid only if all segments defining the measurement are longer than the inter-slice distance.

The geometrical accuracies of measurements performed with CardIQ Vessel Analysis, when related to vessel measurements, are valid only if the vessel diameter is larger than 2mm.

It is not recommended to perform any measurements on a 3D volume rendered model. All measurements should be done from a 2D image.

CAUTION

CAUTION

CAUTION

CAUTION

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Annotations on Filmed or Saved ImagesWhile working on an exam, you can turn off the system annotations and user annotations on the screen (see the Volume Viewer 3 user documentation). If you have done so they will not be present on the filmed or saved images either.Images without annotation may be suitable for teaching purposes, but diagnosis should not be performed with such images.

While working on an exam, you can hide the patient name on the views for increased confidentiality. If you have done so, make sure to show the patient name again on the views BEFORE filming or saving images for diagnostic purposes.When filming or saving images for diagnostic purposes, always make sure the patient name is displayed on all views.

CAUTION

CAUTION

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SegmentationAfter segmentation, perform a visual check of the grafts and manually add missing grafts using Autoselect tool (Add/Remove vessels).

After segmentation, perform a visual check of the coronaries and manually add missing coronaries using Autoselect tool (Add/Remove vessels).

Segmentation [Pro]After Left and Right Ventricle segmentation, check the accuracy of the contours of the segmented ventricles for ES and ED phases by looking on reformatted views.Refine the segmentation if needed by using Autoselect tool (Add/Remove structures).

CAUTION

CAUTION

CAUTION

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Cardiac Filters

Check the displayed annotations to know if the volume is the original one or the filtered one.

Color Identification [Pro]The user shall check and adjust the limits of the color ramp segments to be consistent with the anatomical tissue intensity ranges.

CAUTION

CAUTION

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SOFTWARE SAFETY-RELATED MESSAGESMessages giving information and warnings relating to the current system status are displayed on the Advantage Workstation screens.

Some of these messages may be related to safety issues. For example, a message may warn that a screen or printed image will be enlarged or reduced, and this must be taken into consideration when making a diagnosis. It is important that users take note of and act on the information given in these messages.

The table below shows safety–related messages which may be displayed. In manuals intended for use in countries in which the on–screen language is different from the local language, the table shows the displayed messages and gives a translation in the local language. In manuals intended for use in countries in which the on–screen language is available in the local language, the table is not applicable.

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CHAPTER 3 - SUMMARY OF FUNCTIONS

CardIQ Xpress comprises four main categories of protocols: Vessel Analysis, Ejection Fraction, Volume Rendering and Batch. The purpose of this chapter is to serve as an introduction to the CardIQ Xpress features, and as a quick reference guide.The Vessel Analysis and Ejection Fraction protocols (for both single-phase and multi-phase datasets) consist of a number of steps. The panels associated with each step contain both the instructions on how to perform each step and the necessary controls (buttons, menus, etc.). Section 2 VESSEL ANALYSIS of this chapter summarizes the sequence of operations used with CardIQ Vessel Analysis. For a full description of the Vessel Analysis procedures, refer to Chapter 5. The associated views, controls and measurement accuracy are described in Chapter 6. The customizing of an existing Vessel Analysis protocol is described in Chapter 7.The Volume Rendering protocols are started from the "Cardiac" protocol panel and need little or no further user action. The Cardiac Reformat Batch protocol (for both single-phase and multi-phase datasets) combine setup instructions, semi-automatic batch prescription and batch film/save controls for oblique reformatted short and long axis batch series within the same protocol. Sections 4 VOLUME RENDERING and 6 BATCH of this chapter summarize their use and functioning.For a full description of these protocols, refer to Chapter 10 - Image Review.

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1 MULTI-PHASE DATASETSCardIQ Xpress supports multi-phase cardiac acquisitions i.e., image sets that for each location contain several images, corresponding to different phases in the cardiac cycle.When you load a multi-phase dataset, you will be able to select/drop phases (see phase drop feature description in Chapter 1) and to perform Vessel Analysis, Volume Rendering or Batch functions on a given phase. Then you can switch to another phase to validate the measurement, tracking, or else, in the other phases.The same protocol is used for single-phase and for multi-phase datasets. By switching sync mode on or off in the {review controller} the user can select to perform the functions either on all phases, or only on a single phase.

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2 VESSEL ANALYSISNote: For feature and protocol applicability, check the tables in the CardIQ Xpress options section of

Chapter 1.

Selecting and Loading the ExamTo start using CardIQ Vessel Analysis:• Select the exam, and if necessary the series within the exam, in the AW Patient List.• Start CardIQ Xpress, either directly from the Patient List or from the Volume Viewer 3 "Cardiac" protocol

category.• Select the appropriate CardIQ Vessel Analysis protocol.This can be one of the pre-defined protocols (Left Coronary, Right Coronary, Coronary, Tree VR or Angiographic View) supplied with the application, or a custom protocol defined by the user.

The Left Coronary and Right Coronary protocols allow to study the coronary arteries with their sub-branches. The Coronary protocol allows to study the coronary arteries individually.Tree VR and Angiographic View protocols have been developed to extract and view the aorta, the coronary vessel tree and the cardiac muscle in CT cardiac exams for both single-phase and multi-phase datasets. In brief, the protocols extract and display the aorta, the vessel tree or the cardiac muscle by removing surrounding tissue (bone, lungs, ...) from the 3D volume. They also provide the ability to proceed with tracking of vessels.

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Notes: For Tree VR and Angiographic View protocols to function correctly, it is necessary that the coronary vessels have adequate contrast enhancement. The presence of features such as motion artifacts in the exam can adversely affect the quality of the images.

Because of the limitations in the available data and the different types of image processing used, the Tree VR and Angiographic View images may not clearly show all features of the vascular anatomy (this applies in particular to small and low-contrast features). Tree VR and Angiographic View images should always be used together with the original acquisition images.

The Vessel Analysis protocols function in the same way on multi-phase datasets as on single-phase datasets. Perform the extraction on one phase and then validate the result on the other phases, paging through phases with the vertical slider of the {review controller} or the Phase active annotation. This protocol can be used to create movie loops (beating vessel animations).

For more details on vessel analysis, see Chapter 4 - Starting CardIQ Xpress and Loading the Exam and Chapter 5 - Vessel Analysis - Procedures for details.

CAUTION

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Vessel SelectionAfter starting the protocol, the software performs a 3D filtering operation to extract the cardiac region.The result is displayed as a 3D MIP view, together with an axial and coronal view and the Step 1 protocol panel.The protocol now prompts you to place the points that are necessary to define the branches of the vessel to be analyzed.• To move through the 3D volume, use the same controls as with Volume Viewer 3: 3D cursor, active annotations

and keyboard arrow keys.• To place each point, click with the left mouse button.• The protocol will prompt you for each point in sequence, but when necessary you can return to a point, clear it

and place it again.• You can skip points that are not required for a particular analysis.When all points are placed to your satisfaction, switch to Step 2 of the protocol.You will be prompted to mark the points associated with the vessel branches defined for the specific protocol you have selected. You can, however, re-configure a protocol by adding, modifying or removing branches and intermediate points, as required for a particular type of analysis. Such a re-configured protocol can either be applied to the current session only, or saved and re-used as a new custom protocol.

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Editing, Registering and Saving• In Step 2 of the protocol, select (Accept).

This starts the automatic process of computing the vessel centerline (identification) and vessel cross section at each point along the centerline (quantification).

• When the process is complete, you will have to confirm on the 3D MIP view that the software has identified all vessel branches correctly.A misplaced start point or end point of a branch can lead to the software identifying a part of the cardiac vascular structure entirely different from the one intended.After this, a curved reformatted view, a "Lumen" view and an oblique view are displayed. The curved view shows the entire currently selected vessel branch, the "Lumen" view shows the vessel branch "straightened out", and the oblique view can show either a longitudinal section (L-section) or a cross section (X-section) of the vessel at the cursor position.

• At this stage, you should verify that the software has tracked all vessel branches correctly, and quantified the vessel cross section at each location correctly. Limitations in the data and features such as closely adjacent vessels, may occasionally lead to the software not following a vessel centerline correctly. Use the available views to check that the displayed centerline for each branch matches the desired vessel.The limited resolution and other factors may also lead to cross section quantification errors. These can be identified on the Lumen graph and on the oblique X-section view as irregularities in the contours that do not match the vessel outline. Check the successive cross sections by moving the 3D cursor along the centerline.

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• Both the centerline and the cross section contours can be edited at this stage if necessary (see Chapter 5 - Vessel Analysis - Procedures for details).This can be effective for minor errors. If a wrong branch was identified, repeat Step 1, correcting the tracking points and/or add intermediate points if required. In the case of significant quantification errors, do not use the associated automatic measurements for the report, but perform the necessary measurements manually.

• If you have edited the centerline or the cross section contours, repeat the computation by again selecting (Accept) and then (Back) to close the panel before going to the next step.

• To review the vessel traces again on a 3D view, move to Step 3 and select (Advanced Views) > [VOI].• At this level, if you are dealing with a multi-phase dataset and the Curved view appears to contain some

disruptions, it is possible to perform a phase registration of the exam. Once the registration is over, you can go back to the quantification, which will then be recalculated on the registered volume (for more information on registration, refer to Chapter 5, Section 2 USING THE PROTOCOLS, Step 2 and Chapter 10, Section 3 PHASE REGISTRATION).

• You can also, at any time, save the result of a tracking operation (including Editing and Registering operations) in a 3D object in the Patient List, allowing you to more easily and quickly re-enter this function.

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Exploring the ExamOnce you have verified the correct identification of all vessel branches and the cross section quantification, a range of tools and controls is available to explore the anatomical features and possible pathologies in the vessel:

- You can select each of the vessel branches separately.- You can move to any location in and around the vessel using the 3D cursor,- You can rotate the curved view to examine different features adjacent to the vessel (the curved view is a

"thin", i.e., one-voxel-thick, curved cross section so that features not located on the centerline will rotate into and out of view as the view is rotated).

- The Lumen view shows the vessel with the centerline "straightened out", and a graph alongside the view can show diameter or cross section area as required. You can rotate the Lumen view around the centerline, and adjust the width of the view to display more or less of the adjacent anatomy.

- By default, the oblique view shows a "best" longitudinal cross section (Best L-Section mode). This view is located at the position of the cursor and oriented automatically by the software to show as much of the vessel as possible (plane of maximum curvature). You can also display a longitudinal section view that is tangent to the vessel at the cursor position and that can be rotated around the centerline (L-Section mode), or a view that shows the vessel cross section perpendicular to the centerline at the position of the cursor (X-section mode).

- While using CardIQ Xpress, you can switch any of the views to one of the other types available in Volume Viewer 3, such as baseline or 3D views.

- A tool is provided to allow you to move the cursor on curved and oblique cross-sections and have real time display of the density of the tissues at the cursor level.

- You can deposit a color identification or an ROI to display volumetric statistics or to adjust the color ramp.- You can send findings to the report and add images, measurements, and comments to each finding.

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- You can generate a Movie Loop on the Curved and Lumen view or along a vessel branch on the Oblique view (in Best L-Section, L-Section and X-Section modes).

See Chapter 7 - Vessel Analysis - Views, Controls, Measurements.

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Measurements• In Step 3, mark the locations where measurements are required in the final report.

The protocol prompts you to place measurement points. The automatic measurements computed by the software (quantification) linked to these points such as diameter and cross section area, and between these points, such as distance, angle and volume, will be included in the report.See Chapter 5 - Vessel Analysis - Procedures.

• The protocol prompts you for those measurement points and measurements that have been pre-defined in the protocol. You can, however, configure a protocol by adding, modifying or removing measurement points and measurements as required for a particular type of pathology. Such a re-configured protocol can either be applied to the current session only, or saved and re-used as a new custom protocol.See Chapter 8 - Vessel Analysis - Configuring Protocols.

• To quickly add one or more measurements to be used only in the current session, you can use Step 4 of the protocol. In this step you can define measurement points and measurements (diameter, area, distance, angle volume) that will be included in the current report, but cannot be saved in a custom protocol.You also use this step to include manual measurements in the report, if for any reason the automatic measurements resulting from the automatic quantification are not satisfactory.Moreover, you can, if needed, add at this level a new Simple Reference Point, or a new Double Reference point (one distal and one proximal). In this case, all the measurements computed after the creation of the new Reference Point(s) will be relative to these new point(s).See Step 4 - Add A New Measurement (page 88) in Chapter 5 - Vessel Analysis - Procedures.

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Reports• In Step 5 of the protocol you can examine in tabular form all measurement information that will be included in

the report. At this stage you can still return to the earlier steps in the protocol and make changes, add measurements, etc. as required.

• Once you are satisfied with the report contents, either film (print) the report, or save it as a new series on the image disk of the workstation.The filmed or saved report consists of two main parts: the tables of measurement results and a set of images (screen captures) that is linked to the measurements. The number and type of images in the report may differ depending on the protocol, but generally includes curved and oblique reformatted images for the significant points in the exam.

• During the analysis you can perform additional screen captures and "queue" the resulting images. These will then be added automatically at the end of the filmed or saved report.See Chapter 5 - Vessel Analysis - Procedures and Chapter 12 - Output.

Customizing ProtocolsCardIQ Xpress is supplied as a set of pre-defined protocols.As already mentioned above, you can use these protocols as they are, or use them as a starting point to configure your own custom protocols, to account for individual differences in patient pathology.See Chapter 8 - Vessel Analysis - Configuring Protocols.

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Multi-phase Datasets• When you are performing vessel identification (tracking) on a multi-phase dataset, each time you deposit a

point on the current phase, an equivalent point is automatically computed for all the other phases. Page through the phases to see where the point has been placed.

• Tracking is computed for each phase successively (starting with the current phase). It must be validated for each phase in the MIP view.

• When you are performing a measurement on a multi-phase dataset, each time you deposit a point on the current phase, an equivalent point is automatically computed for all the other phases. Page through the phases to see where the points have been placed.

• A measurement report is generated for the current phase only. Switch to another phase to regenerate it.

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3 EJECTION FRACTION [PRO]The Ejection Fraction protocol is a multiphase protocol dedicated to the calculation of the ejection fraction from the left ventricle volume at end systole and end diastole.Launching the Ejection Fraction protocol automatically launches Cardiac Reformat that displays oblique views of the heart oriented along the short axis and the long axis.

Note: The orientation of Short Axis, Long Axis and Vertical Long Axis views is locked by default.

Follow the panel instructions:• Adjust the Short Axis and Long Axis views if necessary (see Cardiac Reformat protocol) and click (Next): the

Sagittal view turns into an Axial view and the ES/ED Phase Selection panel is displayed,• Click the arrow buttons on the panel to display the different phases on all views,

Note: To display the different phases, you can also right-click the phase annotation or press and hold <ALT> while hitting <Page Up> or <Page Down> .

Note: By default, the first phase to select is the End Systole phase.• Once you have selected the End Systole phase, click (Store Phase) to validate. The panel switches

automatically to End Diastole selection mode allowing you to select the End Diastole phase,• Select the End Diastole phase and click (Store Phase) to validate,

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• Click (Next): the Prepare Segmentation panel is displayed,• For the End Systole phase, place the cursor on the mitral valve using the 4-chamber long axis view for

reference and click (Store Position),• For the End Diastole phase, place the cursor on the mitral valve using the 4-chamber long axis view for

reference and click (Store Position),• Click (Next): the left ventricle is automatically extracted for both the ES and the ED phases according to the

cut planes defined above and the Left Ventricle Model Edition panel is displayed. The papillary muscles are excluded from the subtracted volume.

• Use (Add Structure), (Remove Structure) or (Scalpel) buttons to improve the Left Ventricle segmentation in case LV contours are not accurate for ES and ED phases,

• Click (Next) to display the results:• ED volume (EDV),• ES volume (ESV),• Stroke volume (SV = EDV - ESV),• Ejection Fraction (EF = SV/ED).

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4 VOLUME RENDERINGNote: For feature and protocol applicability, check the tables in the CardIQ Xpress options section of

Chapter 1.

To use the CardIQ Xpress Volume Rendering protocols for a global review of the structures in a CT cardiac exam:• Select the exam, and if necessary the series within the exam, in the AW PatientList.• Start CardIQ Xpress, either directly from the Patient List or from the Volume Viewer 3 "Cardiac" protocol

category.• Select the appropriate Volume Rendering protocol.This protocol can be one of the pre-defined protocols (Cardiac, Heart, Heart Graft or Cardiac Transparency) supplied with the application, or a custom protocol defined by the user.Volume Rendering protocols with names that begin with "Heart" include an automatic segmentation feature that removes the surrounding features (bone, lungs, descending aorta) before displaying the cardiac region.User-defined custom protocols that use the same naming convention will also include this feature.A 3D view using the selected Volume Rendering protocol is displayed. You can now review the exam, and use the Volume Viewer 3 VR Tools panels to modify the VR settings or select another VR preset, as required.The VR protocols function in the same way on multi-phase datasets as on single-phase datasets. Apply the function on one phase and then validate the result on the other phases, paging through phases with the vertical

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slider of the {review controller} or the Phase active annotation.This protocol can be used to create movie loops (beating heart animations).The Cardiac Transparency protocol allows you to display a 3D segmented view of the heart cavities and bones. Transparency of each structure can be adjusted separately. Refer to Chapter 9 - Image Review, Section 2 - Volume Rendering protocols, Cardiac Transparency protocol paragraph for more information.

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5 REFORMATThe basic Volume Viewer 3 Reformat protocol can also be accessed directly from the CardIQ Xpress protocol panel. Refer to the Volume Viewer 3 user documentation for the use of this protocol.

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6 BATCHUse the CardIQ Xpress Cardiac Reformat Batch protocols to view, save and film batch series of reformatted images aligned with the short and long axes of the heart.Launching the Cardiac Reformat protocol computes automatically cardiac orientations. The volume is displayed along Short Axis, Long Axis and Vertical Long axis.

Note: The orientation of Short Axis, Long Axis and Vertical Long Axis views is locked by default.The user checks the consistency of these orientations and ajusts them if necessary.Follow the panel instructions:• Click on the Long Axis button. The Sagittal view is selected and the Long Axis view is unlocked,• Position the cursor on the mitral valve on the Sagittal View,• Rotate the yellow line on the Sagittal view to adjust the orientation of the Long Axis view,• Click on the Short Axis button. The Long Axis view is selected and the Short Axis view is unlocked,• Position the cursor on the mitral valve on the Long Axis view,• Rotate the yellow line on the Long Axis view to adjust the orientation of the Short Axis view.• Click on Short Axis button again to deactivate the edit mode and to display batch icons.The Short Axis batch button is used to prescribe batch series of short axis views only.The Long Axis batch button is used to prescribe batch series of long axis views only.The Vertical Long Axis batch button is used to prescribe batch series of vertical long axis views only.

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Resulting images can then be used with the CardIQ Function package (activated either from the Protocol Panel or from within the protocol).See Chapter 10 - Image Review for a full description.The protocols use an oblique view and a sagittal view. Full instructions on how to set up each batch are shown in the protocol panels. The "batch lines" that define the views to be included in each batch are displayed automatically at each step of the protocols. The Batch Film panel in these protocols, used to review, save and/or film the results, is the same as in Volume Viewer 3.

Defining the Long Axis Plane• On the sagittal view, align the reference line (that defines the plane of the oblique view containing the long axis)

so that it passes through the mitral valve and the apex of the heart.Defining Four-Chamber Long Axis Views• On the sagittal view, align the batch lines parallel to the oblique reference line (long axis plane), to define the

four-chamber long axis views.• Check and if necessary modify the resulting batch, then save and/or film it as required.Defining Short Axis Views• On the oblique view, align the batch lines perpendicular to the long axis, to define the short axis views.• Check, save and/or film the batch as before.Defining Two-Chamber Long Axis Views• On the oblique view, align the batch lines parallel to the long axis, to define the two-chamber long axis views.• Check, save and/or film the batch as before.

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7 PHASE REGISTRATIONThe Phase Registration protocol allows you to align a ventricle or a coronary vessel, in order to suppress the artifacts which often occur in the phases far away from the diastole because of the heart movements.To obtain an improved quality on a given dataset, the software will replace the offset slices by others taken in other phases of the current dataset.You first position the Oblique view so as to have a good vision of the artefact you want to correct. The protocol then allows two types of Registration modes:• Around Cursor: In this case, the registration is performed automatically by the software around the current

cursor position. It will modify slices located no further then 2 cm from the current cursor position.• Between Lines: In this case, the registration on the slices comprised between the two lines you have defined.

This registration can be Automatic (done by the software), or Manual, in which case you will be able to choose in which phase the software will fetch the slices you want to change.

Once you are satisfied with the registration, you can save it in a new 3D object, which will be created in the workstation Patient List.

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CHAPTER 4 - STARTING CARDIQ XPRESS AND LOADING THE EXAM

A CT cardiac exam to be processed with CardIQ Xpress has to meet certain basic requirements.

Select the exam in the AW Patient List, then start CardIQ Xpress either directly from the Patient List or from within Volume Viewer 3.

This chapter describes the image requirements and start-up procedure.

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1 IMAGE REQUIREMENTSCardIQ Xpress accepts CT cardiac image sets such as those acquired with a GE LightSpeed CT scanner or a GE e-Speed Electron Beam scanner.A CT cardiac image set to be used with CardIQ Xpress should meet at least the following requirements (these are the same as those for the basic Volume Viewer 3 application):

- Field of view, matrix size and display center must be the same for all images in the set,

- Orientation and gantry tilt should be the same for all images in the set,

- Tilted acquisitions are not supported for right/left decubitus patient orientations,

- There MUST NOT be two images corresponding to the same location in the set, or within the same cardiac phase in the case of multi-phase datasets,

- The set should include only AXIAL, SAGITTAL, CORONAL or OBLIQUE images. Other types such as screen saves, etc. are not supported,

Note: When loading a CT image set, the CardIQ Xpress software uses the FIRST selected image in the Patient List as a basis for using/discarding the other images selected for building the 3D model. For example, any images having a matrix size or gantry tilt different from that of the first selected image in the Patient List are discarded.

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For use with CardIQ Xpress, the following requirements should also be taken into account:

- For the Vessel Analysis image processing to function correctly, the arterial vasculature in the exam must have adequate contrast enhancement.

- The presence in the exam of artifacts resulting from temporal resolution deficiencies, patient motion or other effects may adversely affect the results of the image processing with any of the CardIQ Xpress protocols.

- The inter-slice distance should be suitable for vascular review and analysis. It MUST be less than 10 mm. Inter-slice distances in the order of 0.625 to 1.25 mm are generally acceptable.

Although CardIQ Xpress will accept and load CT exams with larger inter-slice distances, in practice exams with such inter-slice distances are not suitable for vessel analysis, because of the small diameters of most of the vessels that are essential for the analysis.

It remains the responsibility of the physician to determine whether the inter-slice distance of a given exam is acceptable for use with CardIQ Xpress.Always bear in mind that, within an exam, details with dimensions in the order of or less than the inter-slice distance cannot be identified with an acceptable degree of reliability.

- Anatomical features and pathologies in an exam to be reviewed using the Volume Rendering protocols should NOT be located in the upper or lower end slices of the exam. The end slices are used by the software to correctly compute the 3D images without spurious "end slice" effects, but the features in these slices are not displayed on the 3D views.

An exam to be reviewed using these protocols should contain at least four upper and lower end slices that do not contain any features that require review.This requirement does not apply to exams to be analyzed using the CardIQ Vessel Analysis or Reformat protocols.

CAUTION

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2 START CARDIQ XPRESSTo start using CardIQ Xpress:• Select the exam and series to be analyzed in the AW Patient List (see the AW Basic Display user

documentation for details).The exam should meet the image requirements listed earlier (see page 54).

You can now start CardIQ Xpress either directly from the AW PatientList or from within Volume Viewer 3.

To start CardIQ Xpress from the Patient List:• Select [CardIQ] in the Patient List Application list.• If [CardIQ] is not shown in the list, click on [More...] at the bottom of the list and select [CardIQ] in the Software

Manager menu.

To start CardIQ Xpress from within Volume Viewer 3:• Click on the (Volume Viewer 3) button in the Task Bar.• The Cardiac protocol panel is automatically displayed, and you can select a protocol in this panel.

If more than one cardiac option is installed (e.g., CardIQ and CardEP), first select (CardIQ) at top right in the Cardiac panel, then select the protocol.

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3 SELECT PROTOCOLNote: For protocol applicability, check the table in the CardIQ Xpress options section of Chapter 1.

When you start the CardIQ Xpress software, the Protocol Selection panel is displayed allowing you to choose the protocol you want to use.The same protocol is used for both single-phase and multi-phase datasets.When you move the mouse cursor onto an icon, a help popup will show the function of the protocol. Click on the icon to select and start the protocol and load the exam.The Review Steps window displays a list of protocols allowing you to launch another protocol and to display its associated protocol panel and layouts without having to go to the Protocol Selection panel. The protocols listed by default in the Review Steps window are:• Cardiac Reformat• Ejection Fraction• Angiographic View• Tree VR• Coronary Vessel Analysis• Heart Graft• Cardiac Transparency

Configure the list of protocols displayed and the protocol order at your convenience.

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- The Vessel Analysis protocols have been developed for the detailed analysis of the coronary arteries. Left Coronary, Right Coronary and Coronary protocols allow you to analyze the left and of the right coronary arteries. See Chapters 5 to 7. In addition to reviewing all of the coronary arteries, Tree VR and Angiographic View protocols allow you to extract and view the aorta, the coronary vessel tree and the cardiac muscles. See Chapter 10 - Image Review.

- The Ejection Fraction protocol allows you to compute the ejection fraction, ES, ED and Stroke volumes by segmenting the left ventricle at end systolic and end diastolic phases. See Chapter 8 - Ejection Fraction, Section 2.

- The Volume Rendering (Cardiac, Heart, Heart Graft and Cardiac Transparency) protocols can be used to view the cardiac region and part of the vasculature separate from the surrounding tissue. See Chapter 10 - Image Review, page 176 onwards.

- The Cardiac Reformat batch protocol allows you:

• to display the volume along the Short Axis, the Long Axis and the Vertical Long axis, and to review the volume.

• to prescribe batch series of oblique reformatted images aligned with the short and long axes of the heart, for both single-phase and multi-phase datasets. See Chapter 10 - Image Review, page 190 onwards.

-- The Phase Registration protocol allows you to align a ventricle or a coronary vessel in a multi-phase dataset. See Chapter 10 - Image Review, page 200 onwards.

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Other protocol icons may be available in the Cardiac protocol panel. These can be:

- User-defined custom protocols, created by reconfiguring an existing protocol and saved as a new protocol in the Cardiac protocol category.

- Standard Volume Viewer 3 protocols. Their functions are documented in the Volume Viewer 3 user documentation.

- Protocols that allow you to directly access other applications relevant to the analysis of cardiac images (such as the SmartScore or CardIQ Function applications). See the separate user documentation for these applications.

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5

CHAPTER 5 - VESSEL ANALYSIS - PROCEDURES

CardIQ Xpress is supplied with five pre-defined Vessel Analysis protocols: Left Coronary and Right Coronary, for the imaging and quantitative analysis of the left and the right coronary artery, respectively, with sub-branches; Coronary, for the imaging and quantitative analysis of single coronary arteries; Tree VR [Pro only] and Angiographic View for the extraction of the coronary musculature from the surrounding tissues . These protocols can be used with both single-phase and multi-phase datasets.Each protocol contains the successive steps required to perform an analysis: vessel display adjustment, vessel selection, vessel identification (tracking) and quantification, selection of sections of interest (measurement points), adding quick measurements, report review, and filming or saving of the report.

Use these protocols as supplied, or configure them to your own particular requirements and then save them as new custom protocols.

The current chapter describes the Vessel Analysis procedures, while the next chapter (Chapter 7 - Vessel Analysis - Views, Controls, Measurements) describes the associated special view types and tools, and discusses the measurements that can be performed.

To define custom vessel analysis protocols, refer to Chapter 8 - Vessel Analysis - Configuring Protocols.

The other cardiac image review protocols supplied with CardIQ Xpress are described in Chapter 10 - Image Review.


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1 OVERVIEWYou use the CardIQ Vessel Analysis protocols for rapid and consistent imaging and analysis of cardiac vessel pathologies.The main features are:- Automatic selection: the user adjusts vessel display by adding/removing vessels or structures.- Automatic vessel identification: the user places points to define the start of the vessel and the end of each

branch, and the software automatically identifies and tracks the vessel centerline of each branch.- Multiple-branch analysis: after vessel identification you can select each of the branches for further analysis.- Automatic generation of curved reformatted views that show an entire branch in a single view, using the

centerline as a reference.- Additional oblique view modes: a longitudinal section view (tangent to the centerline), a cross section view

(perpendicular to the centerline) and a "best" longitudinal section view (oriented to show as much of the vessel as possible). Each of these can be moved to show any point along the centerline.

- Phase registration to align a coronary vessel in multi-phase datasets if required.- Automatic vessel quantification: during vessel identification the software also determines the cross section

area and mean diameter at each point along the centerline.- "Lumen" view, showing the currently selected branch "straightened out" together with a curve indicating the

cross section area or mean diameter at each point.- Automatic report generation.


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Each of the CardIQ Vessel Analysis protocols follows the same overall procedure: • Preliminary Step:

- Display adjustment of the enhanced vessels.• Step 1:

- Definition of the vessel(s) to be analyzed.• Step 2

- Automatic computation of the vessel centerline and cross section,- Validation of the results, and editing of the centerline and cross section if required.- Phase registration if required- Intermediate saving of the tracking if required.

• Step 3:- Review of the exam,- Definition of sections of interest to be included in the report.

• Step 4:- Adding new Simple or Double Reference points if required.- Adding measurements if required.

• Step 5:- Review of the measurements to be included in the report- Automatic generation of exam report,- Saving and/or filming of the report.

CardIQ Xpress is provided with five pre-defined Vessel Analysis protocols. Use these as supplied, or use them as "templates" to configure your own custom protocols.


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This chapter describes the common features of the CardIQ Vessel Analysis protocols. The individual features of each protocol such as the points required to define the vessel(s) are documented in the protocols themselves. In most cases you will be using the tools and views provided by the protocols. However, all the other standard and optional tools, view types, etc. that are part of the Volume Viewer 3 application are also fully available.


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2 USING THE PROTOCOLSAfter selecting the exam in the AW Patient List and starting CardIQ Xpress (see Chapter 4 - Starting CardIQ Xpress and Loading the Exam), select the appropriate Vessel Analysis protocol in the "Cardiac" protocol panel.The six steps that constitute each CardIQ Vessel Analysis protocol are described in the following paragraphs.

As a first stage, the software loads the selected exam and constructs the corresponding 3D model in the workstation memory, then performs a 3D filtering operation. This operation extracts the cardiac region by removing extraneous tissue and enhances the cardiac vessels. If you are processing a multi-phase dataset, the 3D filtering operation is performed on all the loaded phases.The result is displayed as a 3D MIP view, together with an axial and coronal view and the protocol panel. The 3D MIP view is initially displayed with the same orientation as the axial view (inferior-to-superior) but you can rotate it as required.The Angiographic View protocol displays an angiographic-like 3D MIP view of the heart, showing:• the aorta,• coronary vessels,• cardiac muscles.

Note : If not displayed, the aorta may be added back with a single click.


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After computation with the Angiographic View protocol, perform a visual check of the coronaries and manually add missing coronaries using Autoselect tool (Add/Remove vessels).On views displayed in MIP mode, the visibility of small anatomical structures such as small coronaries vessels depends on the intensity values in the surrounding tissues.Views that use MIP should always be correlated with the original acquisition images.

You can now proceed with Step 1 of the protocol.

CAUTION


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Preliminary Step - Automatic Selection

Overview [Angiographic View]

The Angiographic View Selection panel allows you to add/remove structures or vessels and to display the aorta.

Note: If a Tree VR protocol has been performed before, the (Add Vessel from Tree VR) button will allow you to retrieve the vessels filtered during the Tree VR build.

Click (Next) to display the Identification panel.


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Overview [Tree VR]

The Tree VR protocol displays a VR view, three reformatted views and the Automatic Vessel Selection panel that allows you to display the aorta and to grow coronary vessels.To display the aorta on the VR view, place the cursor in the aorta on a reformatted view, and click (Display Aorta).To grow coronary vessels on the VR view, proceed as follows:• Using the <Shift> key on a reformatted view, place the cursor in the LMA and click (Display Vessel),• Using the <Shift> key on a reformatted view, place the cursor in the RCA and click (Display Vessel),


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• Using the <Shift> key on a reformatted view, place the cursor on the additionnal vessels you want to display, and click (Display Vessel),

Note: Checking (Display Contours) in the Automatic Vessel Selection panel highlights the selected vessels to help you adjust vessel display.

• Click (AutoSelect) in the Automatic Vessel Selection panel: the Tree VR Selection panel is displayed and allows you to refine vessel display via (Add/Remove Structure), (Add/Remove Vessel), (Dilate) buttons.

Click (Next) to display the Identification panel [Pro only].

Overview [Left Coronary, Right Coronary, Coronary]

Launching the Left Coronary, the Right Coronary or the Coronary protocol directly displays the Identification panel (see next step). Click (AutoSelect) to refine vessel display.


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Step 1 - Vessels to Analyze

The Branch list is the area where you can select the vessel you want to identify.The Instructions/Actions area displays the instructions or actions available for the selected branch.For more information on how to identify vessels, see Chapter 6, Section 1.

Branch list

Hide Panels

Instructions/Actions area

Protocol Configuration area

Go to next step in protocol


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Step 2 - Verification/Edition of the ResultsCardIQ Xpress now first extracts a volume of interest (VOI) that contains the vessel and computes the vessel centerline (identification), then computes the cross section at each point along the centerline (quantification) and displays the result of the tracking on the viewports.At this stage, a message is displayed asking you to accept or reject the identification of the vessel branches.

While the message is displayed, you will have to check whether the software has correctly identified all the vessel branches, using the method described in the paragraphs hereafter (see Verify Vessel Identification on page 73 and Verify Centerlines and Cross Sections on page 75).Once you have checked the tracking, click (Reject) if you are not satisfied with the result. You will then go back to Step 1 and be able to create new points. If you click (Accept), the Edition/Tools panel is displayed allowing you to Edit, Register, Save images (see Edit, Register and Save on page 78), to explore and analyze the exam. Instead, if an error message appears telling you that the tracking has failed, it means that the software was unable to compute a tracking with the elements you gave it. In this case, you can:• go back to step 1 to modify the position of the points in the vessel and define multiple points and bridges if

necessary to extract the desired vessel.


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With multi-phase datasets, all the phases are created automatically as a background task, starting with the current phase. Once the computation is finished, a message for each phase allows you to (Accept) or (Reject) the result for this phase (displayed on the MIP view). If the tracking on one particular phase fails or is rejected, you will be able to go on with the operation, but no quantitative information will be given for the failed or rejected phases.


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Verify Vessel Identification

After the vessel identification and quantification, the centerlines of the vessel branches identified by the software are displayed on the 3D MIP view. As noted before, the start-of-section point should be placed inside the vessel near its origin, not in the aorta, to avoid vessel identification errors.

Note : The software will automatically identify a section extending into the aorta (i.e., beyond the start-of-section point) and include this in the analysis, so that the transition from aorta to coronary will clearly be shown in the images. This extension is also shown on the 3D MIP view.


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The automatic vessel tracking algorithm (vessel identification) relies on the user correctly marking the start and end points of the vessel branches to be tracked.

Incorrectly marking a "start of section" point inside the aorta rather than inside the coronary ostium and/or marking an end point at a location that is not a part of the coronary vessel structure to be analyzed may result in the software identifying a part of the cardiac vascular structure completely different from the one intended.

It is the responsibility of the user to check, for each phase, that all vessel branches to be analyzed have been identified correctly by the software. This verification is more reliable when done on a MIP view.

In the case of multi-phase datasets, the choice of the initial phase conditions the result of the tracking for all the other phases. The user should therefore very carefully choose the most favourable phase before launching the tracking.

CAUTION

CAUTION


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Verify Centerlines and Cross Sections

After confirming that all vessel branches have been identified correctly, the displayed views switch from the initial 3D and baseline views to a curved reformatted view, a "Lumen" view, and a MIP (thick slice) oblique view.An active annotation on each of these views allows selecting which branch of the vessel being analyzed is displayed.- The curved reformatted view shows the entire selected branch in a single view, using the centerline as a

reference.- In the Lumen view, the full length of the vessel section is displayed "unfolded" along the centerline, together

with a graph that can show either the section area or the mean diameter at each point on the centerline.

Oblique viewProtocol panel

Lumen viewCurved view


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- By default, the oblique view is located at the position of the cursor and oriented automatically by the software so as to show as much of the vessel as possible (Best L-section mode). Alternatively, you can display the oblique plane perpendicular to the vessel centerline at the current cursor position (X-section mode).You can also display a view that is oriented tangent to the vessel centerline at the current cursor position and that can be rotated around the centerline (L-section mode), or "unlock" the orientation and rotate the oblique view around the 3D cursor in all directions as required.

Because of the way the Lumen view is generated, by "unfolding" the vessel as a projection at each point of the vessel centerline, the Lumen view by itself is unsuitable for diagnostics. When performing diagnostics, you can use the Lumen view as a reference, correlating the information with the other views. For further details on this view, see Chapter 7 - Vessel Analysis - Views, Controls, Measurements.• Verify that the vessel centerline(s) correspond to the vessel(s) to be analyzed. In the case of complex vascular structures, it is possible for the automatic centerline computation to follow an incorrect trajectory or to identify a wrong branch in the structure.In the case of minor corrections, use the (Edit Center) function (see Edit on page 79) to locally edit the centerline as required. For major corrections it is usually advisable to return to Step 1 and define the vessel again by correcting the tracking points and/or adding intermediate points as required.To review the vessel traces again on a 3D view, select (Advanced Views) > [VOI].

In difficult situations, such as a vessel with a complex trajectory, or vessels touching each other in the images, the automatic vessel tracking algorithm may not always follow the correct trajectory. The user should always examine the computed trajectory before moving on to the next step in the protocol, and if necessary correct the result either by modifying the centerline trace or by correcting the tracking points and/or adding intermediate points, then repeating the centerline detection process.

CAUTION


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• Verify the vessel quantification, as shown by the graph in the Lumen view and by the cross section contours on the oblique view in X-section mode.Local anomalies may occur in the vessel quantification because of limitations in the available data, such as low contrast or motion artifacts. You can remove such local anomalies by using the (Edit Section) function (see Edit on page 79) to edit the cross section contour as required.With some exams, the overall quality of the available data may be insufficient for satisfactory automatic vessel quantification (indicated by a "noisy" graph and irregular cross section contours, see Chapter 7 - Vessel Analysis - Views, Controls, Measurements). In such cases, use the graph and contours for information only, and perform any measurements to be included in the report manually (see Step 4, page 88 onwards).With multi-phase datasets, verification should be done for each phase. If the quantification of one phase has failed or been rejected, the graph of the Lumen view will not be displayed and no automatic measurement will be available.

Note : It is not possible to change the phase during an Edit or a Registration operation.When analyzing a vessel with several branches, make sure to verify each branch separately. Switch between branches by using the active annotations on the views (see Chapter 7 - Vessel Analysis - Views, Controls, Measurements).

Correct vessel quantification is critically dependent on such factors as acquisition image quality and voxel size (image resolution and inter-slice distance), and anomalies may occur because of limitations in the available data. It is the responsibility of the user to verify the result of the vessel identification and

quantification process before using the data for analysis.

CAUTION


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Edit, Register and Save

Once you have accepted the tracking, the other buttons of this panel become accessible:- Click on the (Edit) button to modify the centerline or cross-sections of the tracked vessel.- Click on the (Register) button to align a coronary vessel branch (in multi-phase datasets).- Click on the (Save State) button to save the current state of the tracking.

Go to previous or next step in protocol

Go to Edit

Go to Registration


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Edit

To edit the vessel centerline:• Move the 3D cursor to the approximate position of the section of the centerline trace to be modified.• Select (Edit Center).The centerline is displayed on an oblique L-section view (lower right of the screen).• Point the mouse cursor onto the section, click and hold down the left mouse button, and drag the trace to the desired shape.

Close panel

Edit cross section

Undo edit

Edit centerline


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To edit a cross section contour:• Move the 3D cursor to the position of the section to be modified.• Select (Edit Section).The outline of the contour at the current position along the centerline is shown on an oblique X-section view.• Point the mouse cursor onto the part of the contour to be modified, click and hold down the left mouse button, then drag the contour into shape.You may have to click and drag on several points of the contour to obtain the desired outline.

When you edit a cross section contour, the changes are applied only to the currently selected branch. For a vessel with more than one branch you will have to select and edit each branch separately, including the parts that may be common with another branch.When you edit a centerline, changes done on parts common to several branches areapplied to all branches.

• Select (Undo Edit) to revert to the previous trace or contour if the result of the edit is not satisfactory.• After editing either the centerline or the cross section contours, select (Accept) again to update the vessel analysis computation.• Once you are fully satisfied with the results, select (Close) to close the Edition Tool panel.

NOTICE


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RegisterThis function works in the same way as the Phase Registration protocol, except that you will use the Curved view to perform the registration, which will be centered on the selected vessel branch. • Adjust the cursor, either by dragging the mouse cursor directly on one of the views (usually the Curved view)

on the area of the vessel you want to register, or by using the slider of the Registration panel.• To change the vessel branch, use the Branch active annotation at the top left hand side of the views.• The red lines on the Coronal view (bottom right viewport) represent the area to be registered.• You can perform either an Automatic Registration, by clicking on the corresponding button of the Registration

panel, or a Manual one, by clicking on the (Previous Phase) or on the (Next Phase) button. • The (Undo) button cancels the last performed operation.• The (Restore Orig. Volume) button returns to the original volume for the current phase.

In this mode, the software looks only at the misregistration of the current vessel branch.


Therefore, when using this mode, carefully study the entire volume to check that the automatic registration has not degraded image quality.

Once the registration is over, you can go back to the quantification by clicking on the (Back) button.(For more information on Registration, refer to Chapter 10 - Image Review, Section 3 PHASE REGISTRATION).

CAUTION


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Save StateSave State saves all objects that have been computed.The Save State function allows you to save the current state of the tracking in the Patient List for later use. All editions on centerlines and cross-sections will be saved as well as deposited measurement points.• Click on the (Save State) button to activate the function.• A window pops up requesting you to enter the name of the new created object. This name will appear in the description of the new object in the Patient List, accompanied by the name of the protocol.• If you later reload this object by selecting it in the list and activating the Volume Viewer 3 software, you will be directly brought back in the same protocol, at Step 2 as if you had just performed the tracking, the Edit and Registering operations being memorized and restored just as they were.• With multi-phase datasets, only the current phase is saved and therefore restored.

Note : In order to be able to reload the saved tracking, all the original slices of the saved volume have to be present on the AW. If they are not, you can reload them before starting the protocol.

Note : For Heart Fusion users, Save State will automatically save a model that is compatible with Heart Fusion.


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Explore and Analyze

Explore and analyze the exam using the same range of tools as available in Volume Viewer 3.- Click on the (Advanced Views) to rapidly display the most frequently used view types in the top left view.The primary views used with CardIQ vessel analysis are the curved, Lumen and oblique views (X-section and L-section views), but all the other Volume Viewer 3 view types are also available. The (Advanced Views) button allows you to rapidly display the most frequently used view types in the top left view:

• [Curved]: curved reformatted view,• [VOI]: 3D view in MIP rendering mode showing the volume of interest used for analysis.

You can change this view to show the volume around the centerline corresponding to the width of the Lumen view by clicking right on the Lumen view and selecting [Clip to Width] in the drop-down menu (see Chapter 7 - Vessel Analysis - Views, Controls, Measurements).

• [X-Section]: oblique view in X-section (oblique cross section) mode, • [Navigator]: Navigator view, • [MIP]: 3D view in MIP rendering mode showing the initial volume (i.e., the entire exam),• [L-Section]: oblique view in L-section (oblique longitudinal section) mode.

You can move through the exam using the 3D cursor and the Lumen view cursor line, and rotate the curved, Lumen and oblique L-section views as required. For a full description of the specific features and controls available on the views refer to Chapter 7 - Vessel Analysis - Views, Controls, Measurements.

- Click on the (Stenosis) or (Aneurysm) button to deposit stenosis or aneurysm measurements (see Chapter 6, Section 4).

The (Color Identification) button allows you to deposit color regions based on HU intensities.The (Report Finding) button creates a new finding in the report for you to add comments and images.


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Step 3 - Selection of Section of Interest (does not appear for all protocols)

Overview

Once vessel identification and quantification (Step 2) are satisfactory, explore and analyze the exam using the tools available in Volume Viewer 3. Multiple vessels can be analyzed.You can reconfigure the measurements in the protocol by clicking the (Configure Protocol) button to define and save a new custom protocol. You can also use Step 4 to add measurements that are not part of the protocol (see page 88).

Go to previous or next step in protocol

Current point label and abbreviation(check mark indicates point has been placed)

Configure (customize) protocol


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Measurements

OverviewCardIQ Vessel Analysis automatically computes the vessel cross section (area and mean diameter) for each point on the vessel centerline (quantification). If the results of this quantification process are satisfactory (see page 77 and Chapter 7 - Vessel Analysis - Views, Controls, Measurements) you can use the corresponding automatic measurements in the exam report.The measurements defined in Step 4 of a protocol can be of the following types:

- Distal Reference Point and Proximal Reference Point: all the measurements will have to be located between these two points, which have to belong to the same vessel branch. The created vessel section is represented on Lumen view by a theoretical yellow dotted line. The double reference points will be used to compute the nominal section for each point of the coronary between these two points and to derive the relative measurements. The measurements will be shown in the report both as absolute values (expressed in mm and mm²) and as relative values (expressed in % of the reference).

- If you only mark one of the two reference points, the relative values will be relative to the created point only.- You can place a measurement outside the reference points. In this case, the absolute value in mm and

mm² will appear in the table, but not the relative values. - Auto Diameter: mark a point on the centerline. The associated automatically computed diameter and area

measurements for the point will be included in the report.- Manual Diameter: move the 3D cursor to the appropriate cross section, then place two points on the

oblique X-section view to measure the corresponding diameter (distance).- Length: mark two points on the centerline to measure the distance along the vessel centerline between

the two points.- Angle: mark two points on the centerline to measure the angle between a straight line connecting the two

points and the vertical (RAS coordinate system).


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- Volume: mark two points on the centerline. The resulting measurement is the volume of the section of the vessel between the two points, calculated from the automatic quantification results.

For each measurement, the result will be included in the report together with the associated images (see page 93).

ProcedureThe protocol will prompt successively for each point defined in the protocol. You are not obliged to mark all points: if you do not mark a particular point, the corresponding measurements will not appear in the report.Mark the points in the same manner as when placing points to define the vessel (Step 1). Mostly, you will be using the Lumen view to mark the points, but other views can be used as required.Move the 3D cursor as before by holding down the <Shift> key and moving the mouse on the views. To move the plane of a view (image location) "back and forth" on baseline and oblique views, use the <left> and <right> arrow keys on the keyboard or the active annotations.

• To mark each point, click with the left mouse button. Note that the point is marked at the current location of the mouse cursor, not of the 3D cursor.

• To skip one or more points, click the current point label in the list of points.• To make corrections, click the current point in the list to select the point and mark it again by clicking with

the left mouse button.In the case of multi-phase protocols, each time you deposit a Reference or Measurement point an equivalent point is automatically determined for each of the other phases. To check where the point has been placed on a given phase, switch to this phase.

Note : When placing the points on the views, they are labeled automatically. If any of the labels overlap or hide features on the views, click and drag on the label to move it to a different position.


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Adding and Modifying MeasurementsAfter placing the pre-defined measurement points, at times you may want to add one or more measurements, or modify an existing one.

• To quickly add one or more basic measurements (such as diameter, area, distance, angle or volume) select (Next) to go to Step 4 in the protocol. See page 88.

• For changes to the existing points and measurements in Step 3, select (Configure Protocol).This function allows you to configure the protocol to your requirements by adding, modifying and removing measurement points and related measurements. The resulting protocol can then either be applied to the current session only, or saved and re-used as a new custom protocol.See Chapter 8 - Vessel Analysis - Configuring Protocols for full details.


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Step 4 - Add A New Measurement

Overview

Use Step 4 of the protocol to perform "quick" measurements that are not part of the protocol. These measurements will be included in the report.If you do not require any such additional measurements, skip this step (click on (Next) to go to Step 5).

Go to previous or next stepin protocolClose panel

Modify previous measurementsSelect measurement type,then follow instructions


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Measurements

You can add the following types of quick measurements:• (Auto Diameter): the computed mean diameter and cross section area for a point along the vessel centerline,• (Manual Diameter): distance between two points. This will usually be a diameter (e.g., the actual vessel diameter in the presence of a thrombus where the automatic diameter measurement is that of the lumen) but you can also use this function to measure, e.g., the distance between the vessel wall and nearby bone,• (Length): distance between two points located on the vessel centerline and measured along the centerline,• (Volume): volume of the section of the vessel between two points,• (2 Point Angle): angle between a section of the vessel, defined by two points, and the vessel centerline,• (3 Point Angle): angle between two sections of the vessel, defined by three points. The measurement is the angle between the segment defined by the first and second point and the segment defined by the second and third point.• (Min/Max Length): see Chapter 6, Section 7.

Procedure

To add a quick measurement, select the type of measurement you require. You are prompted to place the necessary point(s). If you wish you can create new reference points for the coming measurements, either just a proximal reference point, defining a simple reference, or a proximal and a distal reference point, defining a double reference. A default name (label) is automatically added in the list in the protocol panel and a default abbreviation on the Lumen view.In the case of multi-phase datasets, each time you deposit a Reference or Measurement point an equivalent point is automatically determined for each of the other phases.To check where the point has been placed on a given phase, switch to this phase.


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After placing the points, you are asked to validate the measurement (to include it in the report). Click on (Yes) to validate, or click on (No) to cancel (the points are removed from the views and not included in the report).To modify the name or the abbreviation of a quick measurement, or remove it:• First select (Modify Previous Measurements). A list of the existing quick measurements is displayed.

To modify the name or the abbreviation of a quick measurement:• Select it in the list by clicking on the label.• Select (Modify) and change the name or the abbreviation in the text fields.• Switch (Film) on or off to determine whether the images associated with the measurement should be included in the report.

To remove a quick measurement:• Select it in the list by clicking on the label.• Select (Remove) to delete the measurement from the list.

Note : To define additional measurements that are to be included in a custom protocol, use (Configure Protocol) in Step 3 or Step 4 (see Chapter 8 - Vessel Analysis - Configuring Protocols). The quick measurements added during Step 4 are used only during the current session, and will not appear in a custom protocol.


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Step 5 - Reports

Use Step 5 of the protocol to review the exam data and measurement information that will be included in the report. Use the arrow buttons at either side of the current page label to move through the pages.If during the review you notice any measurements that need to be corrected, return to Step 3 or Step 4 using the (Back) button and make the necessary corrections (such as adding or moving a measurement point, or changing an annotation).

Go to previous step in protocolClose panel

Report contents:exam data and measurements(exam data illustrated, measure-ments on following pages)

Move through report pagesSave Report

Select OutputSet film format


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You can save or film the report as soon as you are satisfied with the measurement information that will be included in the report.

• Select (Save) or (Film) in the protocol panel as required.

If you are filming the report, you can select the film format (layout of the images on the film in columns and rows). • Open the (Film Format) menu and select [2x2], [2x3], [2x4], [4x4] or [4x5] as required.The software automatically composes and formats the report. The display will cycle automatically through the successive images that will be included in the report. Once the report is composed, you can select (Hide Panels) in the protocol panel to end the analysis, and select the next exam in the Patient List.

If you choose to film the report, it is sent to the same laser camera linked to your workstation that you use to film images from Volume Viewer 3 or from other applications such as the AW Viewer. Refer to the Volume Viewer 3 and AW Basic Display user documentation for details. Filming is performed as a background task: the workstation is available for the next exam as soon as the data have been "queued" for transmission to the laser camera.

If you choose to save the report, it is saved on the image disk as a new series, attached to the current exam. It consists of a set of secondary captures (type SCPT) that can be reviewed using the AW Basic Display Viewer and filmed as required at a later time.In the case of multi-phase datasets, the Film and Save functions only create a report for the current phase. To save another one you must change the phase and re-create the report for the new phase.The filmed or saved report consists of:


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- The exam data and tables of measurement results,- A set of images (screen captures) that is linked to the measurements,- Any screen saves that have been "queued" during analysis.

Exam data and measurementsThe first part of the report consists of a text page with the exam data (exam name, patient name, hospital name, acquisition parameters) and text pages with tables of measurement results. The contents and format of these tables depend on the protocol.

Note : If a reference point is defined in the protocol, measurements are also listed expressed in % relative to the reference section, in addition to the absolute values.

Note : If you have created new reference point(s) at this level, the measurements made with the first reference points will appear as PRef and DRef and will be relative to this first reference point(s) and the measurements made after the creation of the second reference point(s) will appear as PRef-x and DRef-x and will be relative to the new reference point(s).

ImagesThe second part of the report consists of a set of images. The number and type of images in the report depend on the protocol, and on the number and type of measurements in the analysis. They include curved reformatted images for each branch, branch views ("best" plane oblique views of each branch) and oblique X-Section and L-Section images for the measurement points.


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Extra annotations are added automatically on all images that allow you to determine unequivocally the location and orientation of each image, and to which measurement the image refers.

Screen SavesDuring the analysis you can "queue" additional screen captures by means of the [Queue Report Image] menu item on the on-view menus - activated by a right mouse click on the view - (see Chapter 7 - Vessel Analysis - Views, Controls, Measurements). These will be added automatically at the end of a report, when it is saved or filmed.


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CHAPTER 6 - VESSEL ANALYSIS - FEATURES

1 DYNAMIC AVAVessel Analysis protocols provide an improved means of identifying vascular trees. It is called Dynamic AVA and it enables to:- Use the bridging (previously called “Cross Occlusion”) feature as well as intermediary points in multibranches

protocols,- Have a visual feedback of the identified vessels while you are defining them.

At this stage, Step 1 of the protocol, the Vessels to Analyze panel, is displayed together with three baseline views (axial, sagittal, coronal).You are now prompted by the protocol to place the points that are necessary to define the section of the vessel to be analyzed. To move through the 3D volume, you use the same controls as with Volume Viewer 3: 3D cursor, active annotations and keyboard arrow keys.As a minimum, it is necessary to specify the Start point and one other point to move onto the next step in the analysis.After each point is added, you have the ability to display the centerline of the vessel section by clicking the (Show Tracking) button (see paragraph 1.2 “Displaying Branches”).When all centerlines are computed and displayed to your satisfaction or once you have deposited all branch points, click (Next) to go to Step 2 of the protocol. This starts the automatic process of computing the vessel cross section at each point along the centerline (quantification) and applies the default layout for the protocol.


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You can change the default layout in the [Protocol List]. The selected one is added to the Review Steps panel and removed from the [Protocol List].

1-1 Tracking the first branch (from any view)1. Click on view with the left mouse button to place the start point.2. Select in the branch list on the protocol panel the branch you wish to identify.3. Click on view with the left mouse button to place the first branch point.4. If needed, click (Show Tracking) to automatically compute and display the first branch on the 3D view.

1-2 Displaying branchesClick the (Show Tracking) button anytime to display on the right hand screen monitor the following views:- batch cross–section views,- a vertical lumen view,- a 3D VR view of the vessel,- a curved view.

Checking the box next to the (Show Tracking) button activates the automatic display of the vessel after eachdeposited point.

1-3 Extending a branch (from any view)1. Select in the branch list on the protocol panel the branch you want to extend and click on its annotation (on any

view): the branch becomes active.2. Click on any view to deposit a new distal point: the branch is automatically extended to this point and views are

updated.


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1-4 Using Multiple Points per branchIn case of long or tortuous vessels, or of vessels close to bones, you can deposit multiple points on the same branch to avoid incorrect tracking.1. Select the branch you want to track.2. Check the Use Multiple Points box.3. Deposit as many points as you want.

1-5 Correcting a branchIn case of wrong tracking, clicking the (Correct Branch) button will delete the last deposited point and activate the Multiple Points function. You can then deposit as many points as you want on the same branch.

1-6 Identifying a new branchFrom Start point1. Select in the branch list on the protocol panel the new branch you wish to identify.2. Click on view to deposit the distal point of the branch.

From a Bifurcation point1. Select in the branch list on the protocol panel the new branch you wish to identify.2. Click on the (Define bifurc.) button.3. Click an arbitrary position on an existing branch: the branch becomes active from Start point to this new position

(i.e. the bifurcation point).4. Click on view to deposit the distal point of the branch.


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1-7 Deleting a branch (from any view)To remove the branch up to the first bifurcation:1. Drag and drop the branch or its annotation outside the view, or2. Right–click the branch or its annotation and select Remove Branch in the drop–down menu, or3. Uncheck the branch in the protocol panel.

1-8 Renaming a branch (from any view)1. Right–click the branch annotation to display the contextual branch menu.2. Choose a label among the predefined list of labels sorted by anatomy: the branch name is updated, or3. Click Rename and type in new branch name, nickname and comment the new name is stored in thepredefined list of labels and the branch name is updated.

1-9 Defining a new bridge (from any view)1. Select the branch in the branch list on the protocol panel.2. Click (Start bridge).3. Deposit points on view: these new points are considered bridge points for the current bridge.4. Click the (End bridge) button to exit the bridge mode.

1-10 Tracking error casesIf the tracking algorithm cannot find a path (even incorrect) between two consecutives points, the software will automatically define a bridge between these two points.


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2 ADDING/REMOVING BRANCHES

For any Vessel Analysis protocol, you have the ability to add and remove branches to the vessel section being defined for analysis in the Protocol Configuration area.To add a new branch to a section:1. Select the exam, and if necessary the series of the exam, in the AW Patient List.2. Launch Volume Viewer 3.3. Select the protocol category then the desired protocol. At this stage, Step 1 of the protocol, the Vessels to

Analyze panel, is displayed.4. As prompted by Step 1 of the protocol, begin placing the points that are necessary to define the section of the

vessel to be analyzed.5. Click (Add Branch) to add a branch to the section.6. To add a predefined branch label, select the name of the branch from the pop–up menu. The new branch will

now be displayed in the list of branches.To create your own label for a branch, select New branch... from the pop–up menu and in the Add A New Branch dialog box, specify the Point Name, Abbreviation name, and Prompt text for point. Click (Accept) to save the label and display it in the list of branches.

7. Place the new branch point onto a view by clicking the chosen vessel with the left mouse button.The 3D view will update to show the centerline of the new branch.


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To remove a new branch from a section:1. In the list of branches displayed in the Vessels to Analyze panel, uncheck the Done checkbox for the branch

you want to remove. The 3D view will update with the centerline of the removed branch no longer visible.2. If you want to remove the branch completely from the list of branches for the current protocol, then select the

branch and click (Remove Branch).


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3 QUICK AVA

Quick AVA controls

One-Click AVA Two-Click AVA


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Quick AVA provides you with the capability to quickly perform quantitative analysis of a lesion without having to leave the current protocol session.

Quick AVA comprises the following tools available in the Segment (or My Tools) palette:- A one–click AVA tracking tool, which requires just a single click anywhere in the vessel under examination. The

software will automatically track the vessel in both directions proportionally to the diameter of the vessel.- A two–click AVA tool that prompts you to deposit two points: a Start point and an End point. In between these

two points, this tool will calculate the centerline of the lesion.

To perform a one–click AVA analysis:1. From any Volume Viewer 3 or Vessel Analysis protocol, click the one–click AVA button on the Segment (or

MyTools) palette.2. Click the vessel in any view on which you want to perform a Quick AVA analysis. The 3D image will redraw to

display the centerline of the selected vessel based on the proportional vessel diameter along the length of the vessel.

To perform a two–click AVA analysis:1. From any Volume Viewer 3 or Vessel Analysis protocol, click the two–click AVA button on the Segment (or

MyTools) palette.2. Click the start point of the vessel section in any view on which you want to perform a Quick AVA analysis.3. Click the end point of the vessel section in any view. The 3D image will redraw to display the centerline of the

selected vessel section.


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Once the centerline is calculated and displayed, you have the ability to open any AVA protocol panel by clicking on one of the following buttons:- Identification (see Section 1 “Dynamic AVA”)- Verification / Edition- Measurement- Report

The (Start New) button allows you to deposit further traces without restarting Quick AVA one-click or two-click.

The (Delete Traces) button allows you to delete tracking after a QuickAVA one-click or two-click before restarting a new one.


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4 STENOSIS AND ANEURYSM TOOLSThe stenosis and aneurysm tools are available from Step 2 of any Vessel Analysis protocol. These tools allow you to calculate the start and end points of a stenosis or aneurysm, as well as the stenosis or aneurysm dimensions.

4-1 StenosisTo specify a stenosis:1. In Step 2 of the chosen protocol, click (Stenosis).2. Place the proximal reference point by clicking on any view.3. Place the distal reference point by clicking on any view.

The start point, the end point and the minimum diameter of the stenosis are calculated automatically and displayed on the 3D and lumen views. The stenosis measurements annotation is displayed on Reformatted and Lumen views along with the length, area, percentage and minimum diameter of the stenosis.

You have the ability to move any point by clicking and dragging its associated line on the lumen view.


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Lumen and 3D views of a stenosis


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4. If needed, repeat step 1 to step 3 to calculate additional stenosis measurements. The 3D and Lumen views will update and the stenosis measurement annotation menu on Reformatted views will allow you to delete the selected measurement or switch to another measurement.

5. Click (Next) to move to the next step in the protocol.On completion of all steps of the protocol, the exam report will include stenosis measurements and additional stenosis images.

To delete a stenosis measurement, right–click on its annotation and select (Delete).

4-2 AneurysmTo specify an aneurysm, proceed as described in paragraph 4–1 using the (Aneurysm) button. Start point, end point and maximum diameter of the aneurysm are calculated and displayed automatically (as with the Stenosis tool).The aneurysm measurements annotation is displayed on Reformatted and Lumen views along with the length, area, percentage and maximum diameter of the aneurysm.To delete an aneurysm measurement, right–click on its annotation and select (Delete).

4-3 Measurement computation using single/double reference pointTo compute the stenosis/aneurysm measurements, you have the ability to choose a simple reference point (distal or proximal) or a double reference point by right–clicking its annotation.With a proximal reference point (first point deposited), the measurements are computed relatively to the proximal point.


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With a distal reference point (second deposited point, by default for Head & Neck), the measurements are computed relatively to the distal point.With a double reference point (by default for all protocols except Head & Neck), the measurements are computed relatively to the interpolated value between proximal and distal points.


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5 COLOR IDENTIFICATIONThe Color Identification function enables you to create a color–coded volume along the centerline of a defined vessel section. The vessel will be colorized up to the maximum diameter. The function is available for all Vessel Analysis protocols.To use the Color Identification function:1. Click the (Color Identification) button (available in the Verification of the Results panel in Step 2 of the

protocol),2. Click on view to deposit the first point,3. Click on view to deposit a second point: a color ramp is automatically applied around the segment defined by

the two deposited points. It is displayed in all reformatted views as well as curved and oblique views.4. Click the plaque diameter annotation to modify the diameter of the plaque and grab Start and End points on the

lumen view to modify the length of the plaque,5. Click the plaque name annotation to display a drop–down menu allowing you to send the plaque to the Report,

to delete the plaque, or to select another deposited plaque.A discrete color ramp with four segments is displayed on the left hand side of each view (except lumen and 3D views). The color ramp defines a color for a range of voxel values.


6Color Identification of a vessel section


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5-1 Adjusting the Color RampTo adjust the color ramp, click the color ramp on the left–hand side of an oblique, axial or curved view. The Color Map Table panel containing three tabs is displayed.

The Statistics tab displays a table containing the volumetric statistics of each range of voxels corresponding to a color. The third column shows for each color the percentage of colorized volume inside the region of interest. If several color structures have been deposited on the same exam, they can be compared in the same table.

The Configuration tab enables you to configure the color ramp. You can: - Add/Remove color segments. By default, a new segment has no color. - Change the color of a segment by clicking the color cell. A range of colors will display allowing you to select a

new color or to switch to “Black and White”.

Note: If you select “Black and White”, the voxels belonging to this segment will not be colorized but will display their own gray level values. It allows you to create a gap between two color regions.

- Enter a name for a segment to personalize the color ramp. - Adjust the limits of a segment.

Note: These limits can also be adjusted by middle mouse clicking and dragging to left or right the red annotations on the ramp.


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Note: Color segments are adjacent: the maximum value for a segment is the minimum value for the next segment.

- Switch the color ramp from steps to continuous mode by checking the Continuous Ramp box. In continuous mode, the color ramp is smoothed to better detect repartition of gray values within each segment.

Note: Volumetric statistics are not available in continuous mode.

- Click the Presets tab once the color ramp is adjusted.The Presets tab allows you to: - Save the current color ramp as a preset. - Remove the last applied preset. - Apply a different preset.


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6 AUTOMATIC MEASUREMENT POINTSThe Automatic Measurement Points feature allows you to dynamically add automatic measurement points to the currently selected Vessel Analysis protocol.To add an automatic measurement point:1. Click the (Configure Protocol) button (available in the Selection of Section of Interest panel in Step 3 of the

protocol).2. On the Ref. Points panel, click (Add) to display the Add a New Point dialog box.3. From the Diameter type pop–up menu, select [Auto Diameter] and specify a Point name, Abbreviation name

and Prompt text for point.4. Check the Automatic Measurement box to define the point as an automatic point.5. From the Select a Point drop–down menu, select a point to use as reference for the new automatic

measurement. The measurements available will depend on the current Vessel Analysis protocol.6. In the mm text box, enter the number of millimeters that the new measurement will be the point selected in the

previous step.7. Click (Accept) to save the new measurement. This measurement will now be displayed in the Ref. Points list.8. Repeat steps 2 to 4 to add additional automatic measurements.9. If you wish to save the current configuration as a new protocol, then click (Save Protocol). Enter name for the

new protocol in the Save Configuration As New Protocol dialog box and click (Save).10. Click (Close) to return to the Selection of Section of Interest panel (Step 3 of the current protocol).


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To modify an automatic measurement point:1. Click the (Configure Protocol) button (available in the Selection of Section of Interest panel in Step 3 of the

protocol).2. On the Ref. Points panel, click (Modify) to display the Modify a Point dialog box.3. From the Diameter type pop–up menu, ensure that [Auto Diameter] is selected and make any required edits

to the Point name, Abbreviation name and Prompt text for point.4. If necessary, from the Select a point drop–down menu, select new point to use as reference for the automatic

measurement. The measurements available will depend on the current Vessel Analysis protocol.5. In the mm text box, enter the number of millimeters that the measurement will be the selected point.6. Click (Accept) to save the new measurement. This measurement will now be displayed in the Ref. Points list.7. Click (Close) to return to the Selection of Section of Interest panel (Step 3 of the current protocol).


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7 MINIMUM/MAXIMUM LENGTH MEASUREMENTThe Min/Max Length Measurement feature allows you to calculate and display the minimum and maximum length on the wall of the vessel (see Figure below) in addition to the length on the centerline of the vessel.The length is dedicated to the preparation of stent placement.Minimum/Maximum measurements are taken on the quantification contours. Before using minimum/maximum measurements, you shall make sure quantification is correct by using the Edit Section tool.

Minimum/Maximum Length MeasurementNote: The Min/Max Length Measurement feature is optimized for aorta and carotids.


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CHAPTER 7 - VESSEL ANALYSIS - VIEWS, CONTROLS, MEASUREMENTS

The CardIQ Vessel Analysis protocols (Left Coronary, Right Coronary, Coronary, Tree VR [Pro only] and Angiographic View) use several view types that are either specific to or optimized for vessel analysis, in addition to the standard view types available in Volume Viewer 3.

The Lumen view shows the currently selected vessel branch "straightened out". The curved view shows the entire branch in a single view, using the centerline as a reference. For the oblique view additional longitudinal and cross-section modes specific to vessel analysis are available.

In CardIQ Vessel Analysis reports you can include measurements computed automatically by the software and measurements you perform manually. To correctly assess the accuracy of such measurements, you should be familiar with the various factors that affect this accuracy.

This chapter describes the view types and associated controls used with CardIQ Vessel Analysis, and discusses the factors that affect measurement accuracy.


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1 OVERVIEWWith CardIQ Vessel Analysis, you will mostly be using the Lumen view and the curved and oblique reformatted views.The Lumen view shows a vessel branch "straightened out" together with a curve indicating the cross section area or mean diameter at each point. See section LUMEN VIEW.The curved view shows an entire vessel branch in a single view, using curved-plane reformatting with the centerline as the reference trace. Rotate the view as required, to examine all features of the selected branch on the one view. See section CURVED VIEW.The oblique view uses plane oblique reformatting to show part of the vessel. Specific longitudinal section and cross-section modes allow you to examine anatomical details at a given location. Since the view shows a plane ("flat") cross section of the 3D volume, it cannot show an entire vessel with a complex geometry at once, but all geometric relations in the view are maintained so that it can be used both for diagnostics and for measurements. See section OBLIQUE VIEW. The other Volume Viewer 3 view types are also fully available at all times. When used with CardIQ Xpress, some additional features are available on the 3D view. See section OTHER VIEWS.The controls on the views used with CardIQ Vessel Analysis are mostly identical to those that you will be familiar with from Volume Viewer 3. Refer to the Volume Viewer 3 user documentation. Controls that are specific to CardIQ Vessel Analysis are described in this chapter.To correctly assess the accuracy of both automatic and manual measurements performed within CardIQ Vessel Analysis, you should be familiar with the various factors that affect this accuracy. These are discussed in section MEASUREMENT ACCURACY.


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2 LUMEN VIEW

Centerline (not displayed on view)

Width of Lumen "stripe"

Patient name

Curve type (section area or mean diameter)

Cursor line andmeasurement

Graph

Lumen

View typeBranch

Angle of rotationaround centerline

Field of viewRendering mode

(Rfmt or MIP)

Linear position of cursor

Window Width/Level


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OverviewThe Lumen view shows the vessel "unfolded" along the centerline, with the centerline straightened out. You can display either a reformatted "thin" strip (section), or the "tube" around the centerline in MIP mode. If you have defined a vessel with branches, you can switch the display between the branches.The graph can show either the cross section area or the mean diameter. A cursor line allows you to correlate the Lumen view with the other views.You can rotate the Lumen view around the centerline, and change its width if required.The vessel and graph are displayed either vertically or horizontally, depending on the predominant orientation of the vessel in the exam.

GeometryA Lumen view is constructed by transforming the three-dimensional centerline into a straight line and then displaying for each point of the centerline the intersection with the plane perpendicular to the centerline.

This transformation results in geometrical distortion of the displayed anatomical features because the successive intersections are not parallel. For this reason the Lumen view should NOT be used for diagnostic purposes by itself, but always in combination with other views.

Note: The curved reformatted view (see section CURVED VIEW, page 122) is generated by constructing a curved plane that intersects the vessel centerline, then "flattening out" this plane for display on the screen. In this case the geometrical relations in the plane are maintained. Of course, due care should still be taken when interpreting a curved view, because it displays the intersection of the anatomical features with a curved cut plane.

CAUTION


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MeasurementsThe computed value of the section area or mean diameter at the cursor position on the Lumen view is displayed on the graph. You can also use the tools available in Volume Viewer 3 to perform measurements on the Lumen view. However, because of the distorted geometry of the Lumen view, only two types of measurements are possible:

- Distance measurements along a horizontal line (e.g., vessel diameter, or distance between vessel and nearby feature),

- Distance measurements vertically along the centerline.Any other measurements are meaningless.For other measurements, use the Lumen view to 'navigate' along the vessel, and place the measurement points on the plane oblique and/or baseline views where their position in all three dimensions can be determined unambiguously.

GraphThe graph on the Lumen view can show either the section area or the mean diameter.

Note: The section area at a given point is the cross section area of the vessel lumen at that point, as computed by the software and as indicated by the green outline on the cross section oblique view.The mean diameter at a given point is defined as the diameter of a circle with the same area as the section area at that point.

To display either section area or mean diameter, click right on the curve type active (red) annotation and select the desired type in the drop-down menu. From this menu you can also rescale the curve to display a range of values around that corresponding to the current cursor position, or reset the scale to display the full range.


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Cursor LineThe graduated cursor line on the Lumen view indicates the intersection with the plane that contains the 3D cursor and that is displayed in the oblique X-Section view.To position the 3D cursor using the Lumen view, the view must be selected. Move the 3D cursor as usual by pointing with the mouse while holding the <Shift> key. Move the cursor along the centerline in steps by means of the <left> and <right> arrow buttons on the keyboard (the mouse should be positioned on the Lumen view or on an oblique view), or use the vertical slider of the {review controller} with Card. mode off, or use the LP (linear position) active annotation (see next paragraph). On the Lumen view, the 3D cursor is shown as a red tick mark on the cursor line. When you position the 3D cursor using one of the other views, this red tick mark is not displayed.

Active AnnotationsThe active annotations of the Lumen view operate in the same way as elsewhere in Volume Viewer 3.The use of the View Type, DFOV, W/L and Patient Name active annotations is identical. When analyzing a vessel with branches, use the branch annotation to select which branch is displayed. This annotation also appears on the curved and oblique views. When you select a branch on one of the views, the other views automatically display the same branch.Use the Angle annotation to rotate the Lumen view around the centerline of the vessel.Use the rendering mode annotation to select either Reformat (Rfmt) or MIP as the rendering mode for the Lumen view. In Reformat mode the Lumen view shows the "strip" or "ribbon" along the centerline that corresponds to the current angle setting, in MIP mode the view shows the "tube" around the centerline.Use the LP (linear position) annotation to move the 3D cursor along the centerline (the value shown is the 3D distance, measured along the centerline, between the cursor line and the starting point).


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Use the Width annotation to vary the width of the "strip" along the centerline (or the diameter of the "tube" in MIP rendering mode), in order to observe features further away from the centerline.For the curve type annotation, see paragraph "Graph", page 119.

On-View MenuTo use the on-view menu, click and hold right anywhere on the Lumen view (except on the red annotations or the 3D cursor mark), then move down to the required menu item.[Save Image]: saves the full contents of the view (Lumen view, graph, annotations) as a screen save.[Queue Report Image]: places the same information in a "queue" of screen saves, that will be added at the end of a report, when it is saved or filmed.[Clip to Width]: if you have changed one of the other views to a 3D view, this functions clips the 3D view to a "tube" around the vessel centerline with the same diameter as the current width of the Lumen display (also see section 3D View, page 136).[Enlarge]: enlarges the view, so that it takes up the entire viewing area. The menu item changes to [Reset Size] to return to the original size (one quarter of the viewing area).[Reset Pointer]: returns the 3D cursor to the center of the 3D volume.


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3 CURVED VIEW

Curved View

Window Width/Level

Patient name

Orientation

View typeBranch

Angle of rotation

Field of view


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OverviewThe curved view shows the entire currently selected branch in a single view, using curved-plane reformatting with the centerline as the reference trace. You can rotate the view as required, to examine all features of the selected branch on the one view.The curved view does not exhibit the same geometrical distortion as the Lumen view so that it can be used for diagnostics.

GeometryThe curved reformatted view is generated by constructing a curved plane that intersects the vessel centerline, then "flattening out" this plane for display on the screen.

Expressed more accurately, the curved view is constructed as the intersection of the vessel centerline and a vector which sweeps out a curved surface that can be transformed into a plane surface for display while maintaining the geometrical relations in the plane. See illustration. With CardIQ Xpress, the vector is oriented initially parallel to one of the main axes of the RAS coordinate system. Also, rotation is constrained to the planes perpendicular to the main axes.


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Because of the way in which the curved view is constructed, the type of geometrical distortion that occurs on the Lumen view (see section LUMEN VIEW, page 118) does not occur on the curved view; the geometrical relations in the "flattened out" plane are maintained. Nevertheless, all due care should still be taken when interpreting a curved view, because it displays the intersection of the anatomical features with a curved cut plane. In particular, in the case of a complex vessel, "waves" and "folds" in the vessel centerline may result in anatomical features at some distance from the vessel centerline appearing in more than one place on the image when the view is rotated to certain angles.A point to bear in mind is that the curved view is a "thin" reformatted view, not a MIP view. Points that are not actually located on the centerline (e.g., calcifications or bifurcations), will rotate into or out of view when the curved view is rotated.


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OrientationTo interpret the curved view correctly, the following information may be useful.

Curved views:Initial orientation and rotation axis determined by predominant vessel orientation (S-I, R-L or A-P)- The predominant orientation of the vessel (or rather, of the line connecting the end points of the center line)

determines the initial orientation of the view (0° rotation) and the axis around which the view will rotate. See figures above.As an example, for a vessel oriented predominantly S-I, the vector that defines the curved plane in combination with the centerline is oriented A-P, and the resulting view is oriented the same way as a sagittal view, i.e., S-I and A-P. Rotation is around the Z-axis (S-I axis), i.e., the vector remains in the axial plane.

A L

S

A-P

A L

S

R-L

A L

S

S-I


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Display conventions for baseline views

- When a curved view is rotated, the software always displays the view in such a manner, that the orientation matches the display conventions used for the baseline views. See figures above.As a result, when a curved view is rotated it may suddenly flip left-right or rotate 90° in order to match the orientation of the baseline view nearest to the current angle of the display plane. Note that only the display changes, not the axis around which the curved display is rotated.

You also have the possibility of creating a movie loop around a Curved view (refer to Chapter 10 “Movie Creation”, Section 1 “Batch Loop”). In this case the current aspect at the time the movie is started is kept and therefore flip left-right or rotate 90° are not possible.

S

I

A

P

R L

S

I

R LA P

Axial Sagittal Coronal


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MeasurementsSome of the Volume Viewer 3 measurement tools can be used on a curved view. However, because of the particular geometry of the curved view, due care should be taken to interpret such measurements correctly.- Cursor report measurements function normally. You can also be interactively given the density of the tissues

along a specific structure (for example a vessel) by moving the cursor on the view (refer to Section 6 “Density Measurement”).

- Distance and angle measurements on curved views can only be "3D"."3D" measurements return the true 3D distance or angle between points marked on the view, as measured from the 3D volume, irrespective of the curved plane geometry.

- Area measurements are not possible on curved views. Volume measurements will show either the exam volume or the volume of the VOI; these have no practical application for the analysis.

Active AnnotationsThe active annotations on the curved view operate in the same manner as elsewhere in Volume Viewer 3 (see the Volume Viewer 3 user documentation).The use of the View Type, DFOV, W/L and Patient Name active annotations is identical. Use the branch annotation to select which branch is displayed, as on the Lumen view. See page 120.Use the Angle annotation to rotate the curved view. Note that the displayed value of the angle on the curved is not related to that on the Lumen view, because the way the two views are constructed and rotated are different.


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On-View MenuTo use the on-view menu, click and hold right anywhere on the curved view (except for the red annotations or the 3D cursor), then move down to the required menu item.The [Save Image], [Queue Report Image], [Enlarge] and [Reset Pointer] menu items are the same as those of the Lumen on-view menu. See page 121.[Lock Cursor to Trace]: locks the 3D cursor to the vessel centerline on all selected views. Move the 3D cursor as before by holding down the <Shift> key and moving the mouse cursor: the 3D cursor will now move only along the centerline. The menu item changes to [Unlock Cursor] to unlock the 3D cursor from the centerline.


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4 OBLIQUE VIEW

Oblique View

Linear position of cursorfrom start of centerline

Window Width/Level

Patient name

View typeBranch

Field of view

Rendering modeSlice thickness

Section type

Orientation


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OverviewAn oblique reformatted view is a plane ("flat") view that contains the 3D cursor and can be rotated to any orientation.Use the oblique view to examine anatomical details at a given location in the vessel. Since it is a plane ("flat") cross section of the 3D volume, it cannot show an entire vessel with a complex geometry at once, but since it does not exhibit any of the geometrical distortion that occurs on the Lumen and curved views (see earlier), it can be used for diagnostics and measurements in the same manner as the baseline views.

The oblique reformatted views in CardIQ Xpress are the same as in Volume Viewer 3, with the addition of a number of oblique modes specific to CardIQ Vessel Analysis. An X-Section view shows the cross section at the 3D cursor, an L-Section view shows a plane tangent to the vessel, and a Best L-Section view is oriented so as to show as much of the vessel as possible.The vessel cross section contour is shown in green on the views.Otherwise, the views are the same as in Volume Viewer 3, i.e. they are plane reformatted slices. By default a "thick" slice in MIP rendering mode is displayed (using MPVR, see Volume Viewer 3 user documentation). You can modify the slice thickness, or display a "thin" (one voxel thick) slice.


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GeometryAs noted before, the oblique views represent plane ("flat") cross sections of the 3D volume, so that all geometric relations in the plane are maintained.

- The X-Section view shows a reformatted slice that is perpendicular to the vessel centerline and contains the 3D cursor.

- The basic L-Section view shows a reformatted slice tangent to the vessel centerline at the location of the cursor line on the Lumen view, and oriented parallel to the Lumen view at that point. When the Lumen view is rotated around the centerline, the L-section view rotates with it.

- The Best L-Section view is located at the position of the cursor and oriented automatically by the software so as to show as much of the vessel as possible for a given cursor position (plane of maximum curvature).

MeasurementsAll measurements tools available in Volume Viewer 3 can be used on an oblique view. Refer to the Volume Viewer 3 user documentation.

Active AnnotationsThe active annotations on the oblique view operate in the same manner as elsewhere in Volume Viewer 3 (see the Volume Viewer 3 user documentation).The use of the View Type, DFOV, slice thickness, thick-slice rendering mode (Average, MIP, MinIP or VR), W/L and Patient Name active annotations is identical.


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Use the branch annotation to select which branch of the vessel is displayed, as on the Lumen and curved views. See page 120.Use the LP (linear position) annotation to move the 3D cursor along the centerline, as on the Lumen view (the value shown is the 3D distance between the cursor line and the starting point, measured along the centerline).

Note: You can also move along the centerline in steps by means of the <left> and <right> arrow buttons on the keyboard (the mouse should be positioned on the Lumen view or on an oblique view), or use the slider and arrows of the {review controller}.

You can also generate a Movie along the vessel (X-Section, L-Section and Best L-Section modes). For more information, refer to Chapter 10 “Movie Creation”.To change the orientation mode of the oblique view, look for the section active annotation in the lower left corner of the view next to the slice thickness/rendering mode annotation. Click on the annotation and select the mode from the drop-down menu:• [No Lock]: standard oblique view. Use the on-view cube or cross reference lines to rotate the oblique plane

around the 3D cursor position. See the Volume Viewer 3 user documentation.• [XSection]: displays the vessel cross section (perpendicular to vessel centerline) at the current 3D cursor

position.• [LSection]: displays a longitudinal section (tangent to vessel centerline) at the current 3D cursor position,

oriented parallel to the plane of the Lumen view at the same position.• [Best LSection]: displays a longitudinal section at the current 3D cursor position, oriented in the plane of

maximum curvature of the vessel.Use the [Align 3D Views] menu item to align a 3D view with the current orientation of the oblique view (if one of the views has been changed to a 3D view).


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On-View MenuTo use the on-view menu, click and hold right anywhere on the oblique view (except for the red annotations or the 3D cursor) then move down to the required menu item.The [Save Image], [Queue Report Image], [Enlarge] and [Reset Pointer] menu items are the same as those in the Lumen and Curved on-view menus. See page 121.The [Lock Cursor to Trace] menu item is the same as that in the Curved on-view menu. See page 128.[Unlock Orientation]: when selected on an X-section or L-section view, returns the orientation mode to No Lock. See page 132.

Use the [Create Trace], [Clear Last Point] and [Clear Trace] menu items to create 3D traces on the view if required. They do not affect the centerline computed by Vessel Analysis. Use the [Center on FOV], [Center on Object] and [Center on Cursor] menu items to center the oblique view on the current field of view, the current volume of interest or the current 3D cursor position. These menu items are the same as those of the standard oblique view. See the Volume Viewer 3 user documentation.


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5 OTHER VIEWSBy default, a curved view, Lumen view and oblique view are displayed during vessel analysis (after vessel identification and quantification). However, all other Volume Viewer 3 view types are also available. To display a different view type in one of the views, select it in the view type on-view menu. Alternatively, use the (Advanced Views) button in the Step 3 protocol panel to rapidly display the most frequently used view types in the top left view (see page 88):- Curved, - 3D VOI, - X-Section, - Navigator, - 3D MIP,- L-Section.The view type on-view menu also displays the list of previously segmented objects or protocols:- Tree VR, - Angiographic, - Heart Graft, - Heart.

Note: This list may change depending on the CardIQ Xpress option installed on your AW - check protocol applicability table in the CardIQ Xpress Options section of Chapter 1).


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Selecting one of these object/protocol will recall and display the segmented object if previously segmented or will launch the corresponding protocol.

The specific features of the 3D views are described below. For the other Volume Viewer 3 view types, refer to the Volume Viewer 3 user documentation.


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3D ViewWhen used with CardIQ Vessel Analysis, a 3D view includes the vessel centerline and the vessel cross section contour corresponding to the position of the cursor line on the Lumen view. The 3D view can use several different modes.

To display the entire exam volume in HD MIP rendering mode:• Select [3D] in the on-view menu, or [MIP] in the Advanced Views panel.

To display the VOI (Volume Of Interest) computed by the software:• Select [VOI] in the Advanced Views panel.

To display the volume around the centerline corresponding to the width of the Lumen view:• Display a 3D "MIP" or "CVOI" view, then select [Clip to Width] in the Lumen on-view menu.

To align the orientation of the 3D view with that of an oblique view:• On the oblique view, select [Align 3D Views] in the drop-down menu of the section mode active annotation.


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When used with CardIQ Vessel Analysis, the 3D view contains an additional shutter mode active annotation (at lower left, "No VOI" by default).

To display a curved VOI (Volume Of Interest) i.e., a “curved slice” that uses the centerline as a reference and that is displayed in 3D:• Display a 3D "MIP" or "VOI" view, then select [Curved VOI] in the drop-down menu of the shutter mode active

annotation.Adjust the thickness of the 3D “slice” by means of the VOI slice thickness active annotation that appears next to the shutter mode active annotation when a curved VOI is displayed.

To display the 3D view with a spherical "shutter" centered on the 3D cursor (only the volume inside the sphere is displayed):• Display a 3D "MIP" or "VOI" view, then select [Shutter on Cursor] in the drop-down menu of the shutter mode

active annotation.Adjust the diameter of the sphere by means of the shutter size active annotation that appears next to the shutter mode active annotation when a shutter is used. When you move the 3D cursor, the shutter moves with it.


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6 DENSITY MEASUREMENTWhile processing exams with the CardIQ Vessel Analysis protocols, the user can perform density measurements on the images, e.g., if an abnormality is detected on an image.• Click on the (Display Tools) button on the Control Panel and select the X cursor tool in the pull-down menu,

or select directly the X cursor tool from the Review Controller.• Move the cursor onto a reformatted view. • Deposit a point with a left click on the feature you are interested in.

The density of the tissue at this point in Hounsfield values is displayed on the view, as well as the RAS coordinates of the point. This annotation line can be attached to the X cursor by selecting the Linked Annotation box in the ROI Preferences panel (available by clicking Display Tools > Preferences > ROI Prefs). To measure the density at different points, drag the X mark on the view with the left mouse button, or place more points.


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7 MEASUREMENT ACCURACYThis section discusses some of the aspects concerning measurement accuracy that are applicable in particular to the measurements performed with CardIQ Xpress.

The software calculates and displays measurements with a resolution of one decimal place (such as 0.1 mm, 0.1 degree, etc.).You should be aware that the real measurement accuracy is generally considerably less for a number of different reasons.To assess the accuracy of the measurements performed with CardIQ Xpress, you should be fully familiar with the section "Measurement Accuracy" in the chapter "Measurements" of the Volume Viewer 3 User Guide, and with the information below.

SummaryA CT exam (data set) consists of voxels (volume elements). The dimensions of a single voxel determine the lower bound of the measurement accuracy (geometrical accuracy).The final accuracy is further limited by a number of factors.Automatic measurements computed by the software (vessel quantification) are affected by the limitations in the available data. Noise, patient motion, acquisition and reconstruction imperfections, partial volume effects, the small size of some features, etc., all tend to reduce the final accuracy that can be obtained.

CAUTION


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If you are performing multi-phase automatic measurements (multi-phase vessel quantification), you should be conscious that the limitations in the available data concern all the phase datasets you are working with and NOT only the currently displayed one. The calculation of the quantification for one specific phase will depend on the image quality of this particular phase.Manual measurements are further affected by the fact that anatomical features are not of a uniform density, hence dimensions are not unequivocally defined, and the apparent dimension of a feature (e.g., vessel diameter) on the views can change with different display settings. When performing manual measurements under these circumstances, a degree of judgment is usually necessary, and measurements made by different users will not necessarily be identical.Only the geometrical accuracy is mathematically quantifiable. The other factors will have to be evaluated by the user, by examining the image data, to arrive at an assessment of the overall measurement accuracy.

Voxel DimensionsThe image set resolution, i.e., the dimensions of the voxels (volume elements) that constitute the image set, is determined by the size of the field-of-view, the matrix size and the inter-slice distance. In a typical CT image set to be used for vessel analysis, the voxel cross section in the acquisition plane will be in the order of 0.3x0.3 to 0.5x0.5mm for a 512x512 acquisition matrix and a field of view in the order of 15 to 25cm.Ideally, voxels should be isotropic (with the same dimensions along all three axes), i.e., the inter-slice distance should be the same as the voxel dimension in the acquisition plane. In practice, however, considerations such as patient irradiation dose levels will usually lead to the choice of a larger inter-slice distance.To reliably identify and measure the small-diameter vessels that are significant in cardiac analysis, inter-slice distances in the order of 1 to 2mm, and less if possible, should be used. An upper limit of 2.5mm may be acceptable for some cases.


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You should be aware that details with dimensions in the order of or less than the inter-slice distance cannot be identified or measured with any degree of reliability.

Geometrical AccuracyFor CT image sets, the largest dimension of a voxel (normally the inter-slice distance) determines the geometrical accuracy:

- For a distance measurement, the geometrical accuracy of the displayed length is equal to +/- largest voxel dimension,

- For an angle measurement, the geometrical accuracy depends on the length of the segments, and improves as the length of the segments increases. As an example, for an angle measured between segments which are five times larger than the largest voxel dimension, the geometrical accuracy of the displayed angle value is equal to +/- 10 degrees.

- For an area measurement, the geometrical accuracy of the displayed area value is equal to +/- the circumference of the region of interest multiplied by (largest voxel dimension)2 / 2.

The geometrical accuracy defines a lower bound on the overall accuracy that can be obtained. Further limiting factors are the acquisition accuracy, vessel analysis quantification algorithm, partial volume effects, display settings and display resolution.

Note: The accuracy (+/-) values shown in the Vessel Analysis reports corresponds to the geometrical accuracy as defined above.

Distance, angle and area measurements are valid only if all segments defining the measurement are longer than the inter-slice distance.CAUTION


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The geometrical accuracies defined above, when related to vessel measurements, are valid only if the vessel diameter is larger than 2mm.

Acquisition AccuracyThe quality of the vessel analysis, quantification and measurement results is critically dependent on the quality of the original acquisition.Cardiac acquisitions can contain heart beat motion and breathing motion artifacts that will degrade the vessel analysis results. These can be caused by inadequate synchronization with the heart beat, or insufficient temporal resolution.Because of the small size of the coronary vessels, the acquisition parameters (image resolution, inter-slice distance) should be chosen carefully with respect to the dimensions features to be examined. Insufficient acquisition resolution may result in degraded measurement results and the appearance of artifacts such as false stenosis. Insufficient contrast may have the same consequences, and may also result in vessel identification errors.Any errors in the acquisition and reconstruction process such as calibration and slice interpolation errors will be added to the same extent to the measurement error.

Before using an image set for vessel analysis, the user should check for the presence of heart beat motion and other artifacts on axial and coronal images.It is the user's responsibility to insure that sufficiently accurate acquisition parameters are used with respect to the dimensions of the features to be analyzed.Insufficient acquisition resolution (temporal, dimensional and contrast) may result in pathologies or other anatomical features not being visible on the images. It may also result in degraded measurement results and the appearance of artifacts.

CAUTION

CAUTION


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Multi-Phase Measurement AccuracyIn multi-phase datasets, the quality of the vessel analysis, quantification and measurement results for a given phase is critically dependent on the quality of the original acquisition for this specific phase. Before applying a vessel analysis protocol to a multi-phase dataset, the user should check for the presence of heart beat motion artifacts and other artifacts on axial and coronal images for all loaded phases.

Quantification AlgorithmThe vessel quantification algorithm computes the vessel cross-section contour at each point along the centerline. These contours are displayed on the oblique X-section and L-section views. The corresponding computed measurements (cross-section area and mean diameter) are shown by the curve on the Lumen view, and can be included in the report.The algorithm provides a best fit to the data available in the exam. However, the user should be aware that the limited spatial and density resolution of the clinical images processed with CardIQ Xpress also imposes limitations on the attainable measurement accuracy.Correct vessel quantification is critically dependent on such factors as acquisition image quality and voxel size (image resolution and inter-slice distance), and anomalies may occur because of the limitations in the available data. It is the responsibility of the user to verify the result of the vessel identification and quantification process before using the data for analysis.Several factors may combine to degrade the accuracy of the quantification:- The small size of the cardiac vessels (the vessel cross section is defined by only a limited number of voxels), - Low contrast between the vessel and the surrounding tissue,


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- Statistical variations in both the concentration of the contrast product in the vessel and the density of the surrounding tissue, resulting in variations in the apparent diameter of the vessel from point to point,

- Variations in the original image data resulting from the acquisition and subsequent reconstruction process,- Partial volume effects, in particular where calcifications are present,- Motion artifacts.Assess the quality of the quantification by correlating the curve (mean area or mean diameter) on the Lumen view with the display of the vessel on the views.Some indications of degraded quantification are:- Large variations ("noise" and other irregularities) in the curve that do not correspond to clearly visible

anatomical features,- Irregular cross-section contours on the oblique X-section views, that do not match the outline of the vessel. If the anomalies are only local, you can correct these using the Edit, Register and Save functions (see page 78). Otherwise, it is preferable to consider the automatic measurements as approximate, and perform measurements manually (see Step 4 - Add a New Measurement in Chapter 5 - Vessel Analysis - Procedures, page 88 onwards).

Note: The factors that tend to degrade the quantification results do not affect the vessel centerline tracking process to anywhere near the same degree. As a result, you can generally obtain satisfactory vessel identification and display, even when the quantification results may be indicative only.

If you are performing multi-phase vessel quantification, assessment of the quality of quantification must be done for each phase.

Partial Volume EffectsIn CT exams, the value of a voxel is the weighted average for all materials in the voxel. Because of the high attenuation coefficient of calcium, even a small amount of calcium in a voxel will weigh its value towards that of calcifications or bone, so that the entire voxel appears to be calcifications or bone.


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In vessel analysis, this partial volume effect will tend to make calcifications in the vessels appear larger than they are in reality, and hence affect the measurement accuracy.Another partial volume effect occurs at the interface between two tissue types with different densities. The transition between the two densities is not a step, but partial volume voxels with intermediate values occur at the interface. This affects the measurement accuracy, because the dimension of a feature is not sharply and unequivocally defined, but depends on to what extent the partial volume voxels are taken into account.

Display Settings and Display ResolutionSince anatomical features are rarely of a uniform density, the apparent dimension of an anatomical feature can change when you change the display settings (window width and level).The automatic measurements computed by the CardIQ Xpress software are not affected by this, because the software does not rely on the display settings for vessel identification and quantification. However, when you place the measurement points yourself, e.g., for an additional diameter measurement, the apparent diameter can differ by one or more voxels depending on the W/L settings, thereby adding another factor of uncertainty. When four views are displayed on the workstation screen, each view has a display resolution of 512x512 pixels, and you obviously cannot place a manual measurement point with a precision better than a single pixel. Since most exams used for vessel analysis are based on a 512x512 acquisition matrix, display resolution normally does not impose a further limitation on accuracy, the more so because in most cases the display field of view (DFOV) used during analysis is smaller than the acquisition field of view.


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CHAPTER 8 - VESSEL ANALYSIS - CONFIGURING PROTOCOLS

CardIQ Xpress is supplied with five pre-defined Vessel Analysis protocols: Left Coronary and Right Coronary for the imaging and quantitative analysis of the left and the right coronary artery, respectively, with sub-branches; Coronary for the imaging and quantitative analysis of individual coronary arteries; Tree VR [Pro only] and Angiographic View for the extraction of the coronary vessel tree structure and aorta (and myocardium for Angiographic View) from the surrounding tissues. Use these protocols as they are, or use them as a starting point to configure your own custom protocols, to account for individual differences in patient pathology.This chapter describes how to create custom Vessel Analysis protocols as required, by configuring the pre-defined protocols through adding, modifying or removing points.


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1 PRE-DEFINED PROTOCOLSThe Left Coronary, Right Coronary and Coronary protocols have been defined for the analysis of the coronary arteries.The tracking (vessel definition) points in Step 1 of these protocols comprise the start of the section to be analyzed and a number of branches.The pre-defined Left Coronary protocol contains seven tracking points (six branches): Start of section, Left main artery, Left anterior descending artery, First diagonal, Second diagonal, Left circumflex artery and Left marginal branch.The pre-defined Right Coronary protocol contains four points: Start of section, Right Coronary Artery, Posterior Descending Artery and Posterior Lateral Branch.Neither of these pre-defined protocols contains intermediate tracking points (see page 151 for details).The pre-defined Coronary protocol contains one branch; it allows to deposit intermediate points to improve the reliability of the tracking process.The pre-defined Tree VR and Angiographic View protocols contain nine tracking points: Start, Left Anterior Descending Artery, First Diagonal, Second Diagonal, Left Circumflex Artery, Left Marginal Branch, Right Coronary Artery, Post Descending Artery and Post Lateral Branch.The measurement points in Step 3 of these protocols comprise a proximal reference point, a distal reference point and a generic set of section-of-interest points identified as A-Z.The associated measurements in the report include the mean diameter and the cross section area at each of these points, expressed in mm / mm2 and in % relative to the reference.


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2 CUSTOM PROTOCOLS

Overview

You can re-configure the pre-defined protocols to meet your own particular requirements.For incidental changes, simply re-configure the protocol before or during the current analysis session.To set up a custom protocols, re-configure an existing protocol using a representative exam, then save the protocol under a new name.To add, modify or remove tracking points (used to define the vessel to be analyzed), re-configure the protocol in Step 1 "Define Section to Analyze". See page 150 onwards.To add, modify or remove measurement points or related measurements between points, re-configure the protocol in Step 3 "Select Section of Interest". See page 155 onwards.If your changes are only to be used for the current exam, use the modified protocol to perform the analysis, then save or film the report as required. If you also intend to re-use the modified protocol for future sessions, save the protocol under a new name before closing it. See page 166.

Note: To quickly add one or more basic measurements (such as diameter, area, distance, angle or volume), to be included in the report of the current session only, you do not need to re-configure the protocol: use Step 4 "Add a New Measurement" of the current protocol. See Chapter 5 - Vessel Analysis - Procedures.


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Configuring Tracking (Vessel Definition) Points

To configure the tracking points:• Display Step 1 "Define Section to Analyze" (if necessary use the (Back) button).• Select (Configure Protocol) to open the Configure Tracking Points panel.

The list of existing tracking (vessel definition) points is displayed.

Save protocolClose panel

List of tracking points

Select (Add), (Modify) or (Remove)

Point typeClick on label to select a point(to add a point under the selected point, or to modify or remove a point)


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There are three types of points:

- Root: this is the start of the section to be analyzed. This point cannot be modified or removed.- Intermediate: use this type to better define the vessel, and in particular to remove ambiguities where the vessel identification algorithm might not identify the correct volume of interest.- Branch: use this type to define branches. The vessel identification algorithm will track the vessel from the start ("root") point up to each branch point separately.

Note: When adding or modifying points, "Intermediate" and "Branch" are the only options available.

Note: Occasionally, in complex situations, it may occur that the vessel tracking algorithm does not succeed in identifying the volume of interest correctly (this may be indicated by an error message, or it may be obvious from the display).This can be resolved by adding one or more intermediate tracking points. These will be used by the vessel tracking algorithm as additional information while determining the volume of interest. They are not used by the subsequent vessel identification process, so that the computed vessel centerline may not pass exactly through such intermediate points.

Root

Interme-diate

Branch

Branch


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• Select the point in the list under which you want to add a point, by clicking on its label.• Select (Add) to open the Add a Tracking Point panel.

Accept entries andreturn to previous panel

Enter abbreviation for pointEnter name for point

Select tracking type from menu

Enter prompt text for point

Cancel and return to previous panel


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• Select the Tracking type: [Intermediate] or [Branch].• Enter the necessary information in the three text fields. Click inside each field to select it, then enter the text

from the keyboard. For corrections, move the text cursor with the left and right arrow keys or by clicking with the mouse. You can insert characters from the keyboard, or delete the character before the text cursor with the <BackSpace> or <Del> key.Point name: enter the full descriptive name of the point. Try to avoid names longer than the width of the text entry field (40 characters max.).Abbreviation name: enter an abbreviation for the name (or the full name if it is short enough). The abbreviation will be displayed on the views. Limit the length to about ten to twelve characters at most.Prompt text for point: enter the instructions ("prompt") that will be shown in the "Define Section to Analyze" panel, indicating how and where to place the point. The prompt text does not need to fit inside the text field: when you reach the right edge it will scroll automatically. Type the text as one long sentence: when displayed afterwards it will wrap round automatically. Do not use the <Enter> key.

Note: If you are adding a new point for the current session only, the prompt text can be a brief reminder to yourself, such as "Above bifurc.", or can even be left blank.However, if you intend to save the protocol for future use, it is advisable to write out the prompt text fully, such as "Click with the left mouse button to select a point just above the bifurcation". This avoids any ambiguity during later use of the protocol, either by yourself or by another user.

• Select (Accept) to validate the new point and return to the Configure Tracking Points panel, or (Cancel) to annul the operation.

Note: If you entered a name or abbreviation that already exists, a message will alert you to this and the new point will not be entered in the list.


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To modify a point:• Select the point in the list by clicking on its label.• Select (Modify) to open the Modify a Tracking Point panel.• Modify the Tracking type and the information in the three text fields (point name, abbreviation and prompt

text) in the same manner as described above for a new point.• Select (Accept) to validate the modification and return to the Configure Tracking Points panel, or (Cancel)

to annul the operation.

To remove a point:• Select the point in the list by clicking on its label.• Select (Remove).

The point is deleted from the list without requiring user confirmation.

Notes: Take care when removing points. Once deleted they cannot be restored.The starting point (type "Root") cannot be removed.

At this stage you can save the protocol (see page 166) or return to the panel for Step 1 "Define Section to Analyze" by clicking on the (Back) button.


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Configuring Reference Points and Measurements

Overview

When configuring the protocol, a distinction is made between measurement points and related measurements.

The reference points are located on the centerline of the vessel and associated with measurements such as diameters and cross section area at that point.The measurements refer to measurements between points, such as angles, or the length or volume of a section between two points. If the points do not already exist in the protocol you must add them before you can add the related measurement.

You add, remove or modify reference points and measurements separately (see page 156 and page 161, respectively).


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Configuring Reference Points

To configure the reference points:• Display Step 3 "Select Section of Interest" (if necessary use the (Back|Next) buttons).• Select (Configure Protocol) to open the Protocol Configuration panel with the Ref Points tab selected by

default.


Add, modify, remove points


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The list of existing reference points is displayed. There are three types of points:- No Diameter: no diameter or cross section area measurements will be associated with the point.

You may want to define such a point for a related measurement (such as an angle, length or volume, see page 161), if the diameter and area measurement at the point itself are not required in the report.

- Auto Diameter: all diameter and area measurements for the point will be computed automatically by the software and included in the report.

- Manual Diameter: only a manually defined diameter (distance) measurement will be associated with the point. To perform such a measurement during analysis, move the 3D cursor to the appropriate cross section, then place two points on the oblique X-section view. You may want to include these instructions in the "prompt" text (see below).

An example would be the presence of a thrombus or calcification, where an automatic measurement will show the diameter of the lumen, and the user may want to add a measurement of the actual vessel diameter.


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To add a new point:• Select (Add) to open the Add a New Point panel.

• Select the Diameter Type: [No Diameter], [Auto Diameter] or [Manual Diameter].• Enter the necessary information in the three text fields. Click inside each field to select it, then enter the text

from the keyboard. For corrections, move the text cursor with the left and right arrow keys or by clicking with the mouse. You can insert characters from the keyboard, or delete the character before the text cursor with the <BackSpace> or <Del> key.Point name: enter the full descriptive name of the point. Try to avoid names longer than the width of the text entry field (40 characters max.).

Accept entries andreturn to previous panel

Enter abbreviation for pointEnter name for pointSelect measurement type

("diameter") from menu

Enter prompt text for point



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Abbreviation name: enter an abbreviation for the name (or the full name if it is short enough). The abbreviation will be used in the report lists, and displayed on the views. Limit the length to about ten to twelve characters at most.Prompt text for point: enter the instructions ("prompt") that will be shown in the "Select Section of Interest" panel, indicating how and where to place the point. The prompt text does not need to fit inside the text field: when you reach the right edge it will scroll automatically. Type the text as one long sentence: when displayed afterwards it will wrap round automatically. Do not use the <Enter> key.

Note: If you are adding a new point for the current session only, the prompt text can be a brief reminder to yourself, such as "Mark bifurc.", or can even be left blank.However, if you intend to save the protocol for future use, it is advisable to write out the prompt text fully, such as "Click with the left mouse button to select a point just above the bifurcation". This avoids any ambiguity during later use of the protocol, either by yourself or by another user.

• Select (Accept) to validate the new point and return to the Protocol Configuration panel, or (Cancel) to annul the operation.

Note:If you entered a name or abbreviation that already exists, a message will alert you to this and the new point will not be entered in the list.

To modify a point:• Select the point in the list by clicking on its label.• Select (Modify) to open the Modify a Point panel.• Modify the Diameter type and the information in the three text fields (point name, abbreviation and prompt

text) in the same manner as described above for a new point.


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• Select (Accept) to validate the modification and return to the Protocol Configuration panel, or (Cancel) to annul the operation.

To remove a point:• Select the point in the list by clicking on its label.• Select (Remove).

The point is deleted from the list without requiring user confirmation.

Note: Take care when removing points. Once deleted they cannot be restored.

At this stage you can configure the related measurements (see page 161), save the protocol (see page 166) or return to the panel for Step 3 "Select Section of Interest" by clicking the (Close) button.


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Configuring Measurements

To configure the measurements:• Display Step 3 "Select Section of Interest" or Step 4 “Measurements” (if necessary use the (Back|Next)

buttons).• Select (Configure Protocol) to open the Protocol Configuration panel.


Add, modify, removemeasurement


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• Select the Measurements tab.

The list of existing measurements is displayed. There are three types of measurements:

- Length: distance measured along the vessel centerline between the two points.- Volume: volume of the section of the vessel between the two points.- Angle: angle between a straight line connecting the two points and the vertical (RAS coordinate system).


List of measurements

Select (Add), (Modify) or (Remove)

Measurement typeClick on label to select a measurement(to add a measurement under the selected one,or to modify or remove a measurement)


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To add a new measurement:• Select (Add) to open the Add a New Measurement panel.

• Enter the necessary information in the two text fields. Click inside each field to select it, then enter the text from the keyboard. For corrections, move the text cursor with the left and right arrow keys or by clicking with the mouse. You can insert characters from the keyboard, or delete the character before the text cursor with the <BackSpace> or <Del> key.Measurement name: enter a descriptive name for the measurement. Try to avoid names longer than the width of the text entry field (40 characters max.).

Accept entries and returnto previous panel

Enter abbreviationEnter name for measurement

Select measurement type from menu

Select start point in "From point" list


Select end point in "To point" list

Scroll list if necessary

Images in report on/off


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Abbreviation name: enter an abbreviation for the name (or the full name if it is short enough). The abbreviation will be used in the report lists, and displayed on the views. Limit the length to about ten to twelve characters at most.

• Select the measurement type: Measure a [Length], [Volume] or [Angle].• To include only the measurement values in the report: set (Film) to off.

To include both the measurement values and the corresponding images in the report: set (Film) to on.

• In the side-by-side lists, select (highlight) the start point in the From Point list, and the end point in the To Point list. If necessary use the up/down buttons under each list to scroll through the list.You can only set up measurements between existing points. To set up measurements between points not yet in the list, first return to the Protocol Configuration panel and create the new points as described earlier (page 156).

• Select (Accept) to validate the new measurement and return to the Protocol Configuration panel, or (Cancel) to annul the operation.


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To modify a measurement:• Select the measurement in the list by clicking on its label.• Select (Modify) to open the Modify a Measurement panel.• Modify the information in the two text fields (measurement name and abbreviation), the measurement type,

the From and To points, and select whether to include the images in the report ( (Film) button), in the same manner as described above for a new measurement.

• Select (Accept) to validate the modification and return to the Protocol Configuration panel, or (Cancel) to annul the operation.

To remove a measurement:• Select the measurement in the list by clicking on its label.• Select (Remove).

The measurement is deleted from the list without requiring user confirmation.

Note: Take care when removing measurements. Once deleted they cannot be restored.At this stage you can configure the measurement points (see page 156), save the protocol (see page 166) or return to the panel for Step 3 "Select Section of Interest" by clicking the (Close) button.


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Saving the Protocol

If you intend to use the modifications of the protocol only for the current analysis session, return to Step 2 or Step 4 after you have made the modifications, perform the analysis and save or film the report, then close the protocol. The modifications of the protocol will not be saved.

If you want to save the modified protocol for future use, you can do this at any stage before you actually close the protocol. To do so:• Select (Save Protocol) in the Configure Tracking Points or Configure Protocol panel.

If necessary, first move to either Step 2 or Step 4 and select (Configure Protocol).• In the Save Configuration as New Protocol panel that is displayed, click inside the Name: text entry field,

and enter the new name from the keyboard.• Select (Save) to save the protocol, or (Cancel) to annul the operation.

If the name already exists, a message will alert you to this. In the message window, select (Cancel) to repeat the operation with a different name, or (Overwrite) to replace the existing protocol with the modified one.

The protocol will be saved in the same Volume Viewer 3 protocol category as the original protocol.If the original protocol is a multi-phase protocol, the saved protocol will also be multi-phase. The chosen name of the new protocol will automatically be followed by “MP”.After saving the protocol, return to the Step 2 or Step 4 panel using the (Back) buttons.


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Deleting a Protocol

If you regularly create customized protocols, you may at some point want to delete one or more protocols, in particular if you have created successive versions of the same protocol and you want to delete the earlier versions.To delete a protocol:• From the Patient List: first start Volume Viewer 3 or CardIQ Xpress.

If Volume Viewer 3 or CardIQ Xpress is already running, close the current protocol and select (New Protocol).• In the Select a protocol category panel, select the required category ("Cardiac" for CardIQ Xpress protocols).• In the Select a protocol panel, click on (Delete Protocol) under the list. The panel changes to Select a

protocol to be removed.• Click on the icon of the protocol you want to delete. A confirmation message "Do you really want to delete this

protocol?" is displayed. Click on (Yes) to confirm, or on (No) to cancel the operation.If required you can remove more than one protocol by selecting and deleting them one after the other.

• Click on (Cancel) to close the panel and return to the Select a protocol category panel.

Note: The pre-defined protocols supplied with CardIQ Xpress cannot be deleted.


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9CHAPTER 9 - EJECTION FRACTION [PRO]

CardIQ Xpress Pro is supplied with the Ejection Fraction protocol, for the imaging and quick computation of the left ventricle ejection fraction parameters. This protocol contains the successive steps required to perform left ventricle segmentation: cardiac reformat, (ES) and (ED) phase selection, cut plane selection, edition of the segmented volume, display of the heart functional parameters.

The Ejection Fraction protocol steps include the Cardiac Reformat protocol (as a first step) to the computation of the left ventricle ejection fraction.

The Ejection Fraction protocol uses several view types: Short Axis, Long Axis, Vertical Long Axis that come in addition to the standard view types available in Volume Viewer 3.

This chapter describes the view types and associated controls used with the Ejection Fraction protocol.

All standard and optional tools, view types, etc. that are part of the Volume Viewer 3 application are also fully available at all times. Refer to the Volume Viewer 3 user documentation for full information on those functions.

For more information about the Cardiac Reformat step, refer to Section 2 of Chapter 9, Image Review.


9

1 EJECTION FRACTION PROTOCOLThe Ejection Fraction protocol is a multiphase protocol dedicated to the calculation of the ejection fraction from the left ventricle volume at end systole and end diastole.Launching the Ejection Fraction protocol automatically launches Cardiac Reformat that displays oblique views of the heart oriented along Short Axis and Long Axis.

Note: The orientation of the Short Axis, the Long Axis and the Vertical Long axis is locked by default.Follow the panel instructions:• Adjust the Short Axis and Long Axis views if necessary (see Chapter 9, Section 2 Cardiac Reformat batch

protocol) and click (Next): the Sagittal view turns into an Axial view and the ES/ED Phase Selection panel is displayed,


9

• Click the arrow buttons on the panel to display the different phases on all views,

Note: To display the different phases, you can also right-click the phase annotation or press and hold <ALT> while hitting <Page Up> or <Page Down> .

Note: By default, the first phase to select is the End Systole phase.• Once you have selected the End Systole phase, click (Store Phase) to validate. The panel switches

automatically to End Diastole selection mode allowing you to select the End Diastole phase,• Select the End Diastole phase and click (Store Phase) to validate,• Click (Next): the Prepare Segmentation panel is displayed,


9• For the End Systole phase, place the cursor on the mitral valve using the 4-chamber long axis view for

reference and click (Store Position),• For the End Diastole phase, place the cursor on the mitral valve using the 4-chamber long axis view for

reference and click (Store Position),• Click (Next): the left ventricle is automatically extracted for both the ES and the ED phases according to the

cut planes defined above, and is displayed in the upper left viewport. The left ventricle contours appear in green in the Short and Long Axis views. The Left Ventricle Model Edition panel is displayed allowing you to improve the left ventricle segmentation if necessary,

Note: Papillary muscles are automatically excluded from model.


9• Use (Add Structure), (Remove Structure) or (Scalpel) buttons in case left ventricle contours are not accurate

for ES and ED phases,• Click (Next) to display the results:

• ED volume (EDV),• ES volume (ESV),• Stroke volume (SV = EDV - ESV),• Ejection Fraction (EF = SV/ED).

Note: Results are displayed on both the Ejection Fraction results panel and the VR view.


9


10CHAPTER 10 - IMAGE REVIEW

The primary CardIQ Xpress tools for the review and analysis of CT cardiac exams are the Vessel Analysis protocols described in the previous chapters.

Additionally, CardIQ Xpress is supplied with:- An Ejection Fraction protocol [Pro only] to calculate the ejection fraction from the left ventricle volume at

end systole and end diastole (see Chapter 8 - Ejection Fraction protocol),- Volume Rendering protocols customized for cardiac image review,- A Batch protocol to view, save and film batch series of reformatted images aligned with the short and long

axes of the heart.- A Phase Registration protocol (for multi-phase datasets) to align a ventricle or a coronary vessel.

This chapter describes the use of the Volume Rendering, Batch and Phase Registration functions.

All standard and optional tools, view types, etc. that are part of the Volume Viewer 3 application are also fully available at all times. Refer to the Volume Viewer 3 user documentation for full information on those functions.


101 VOLUME RENDERING PROTOCOLSNote: For feature and protocol applicability, check the tables in the CardIQ Xpress options section of

Chapter 1.

CardIQ Xpress is supplied with a set of Volume Rendering (VR) protocols (Cardiac, Heart, Heart Graft and Cardiac Transparency) optimized for cardiac imaging.VR "Heart" protocols (where the name of the protocol begins with "Heart") first automatically segment the exam to extract the cardiac region, then display it using VR presets optimized for cardiac imaging. The other VR protocols in CardIQ Xpress use volume rendering to display the entire exam, without segmentation.Use these protocols to obtain a global view of the cardiac region, to examine the overall spatial relations and those parts of the vasculature located on the outside of the region. You will mostly use the protocols as a starting point, then adjust the settings to optimize the display.To examine the vessels separately in more detail, use the Vessel Analysis protocols.See Chapter 5, Chapter 7 and Chapter 8.This section describes the protocols and provides a summary of the principles of Volume Rendering and its controls, with particular reference to its use for cardiac imaging. For a full description of volume rendering, consult the Volume Viewer 3 user documentation.


10On views displayed in volume rendering mode, the visibility of anatomical features is determined by curve type (threshold mode), opacity thresholds and maximum opacity settings. Essential anatomy or pathologies may not be visible for a given setting of these parameters.Views that use volume rendering should always be correlated with the original acquisition images.

"Heart" ProtocolsThe CardIQ Volume Rendering protocols with names that begin with "Heart" include an automatic segmentation feature.They automatically segment the exam to extract the cardiac region by removing surrounding structures such as the sternum, ribs, spine and lungs, and unconnected blood vessels such as the descending aorta, from the 3D volume. The remaining cardiac region is then displayed using volume rendering.The volume rendering settings are determined by the VR preset included in the protocol. You can select other VR presets, or use the Volume Viewer 3 VR Tools to modify the settings.When used with a multi-phase dataset, the Heart protocols perform the extraction of the cardiac region for all the phases. They can be used to generate a cine loop (movie) of a beating heart. For more information, refer to Chapter 10 “Movie Creation”.

Note: To include the automatic segmentation feature in a custom protocol created by modifying an existing VR protocol, save the protocol under a new name that also begins with "Heart".

CAUTION


10Note: The segmentation process removes the external structures from the 3D model in the workstation

memory. To return to the original exam volume, select [Restore volume] in the on-view menu (right mouse button) or switch to another protocol.

Note: Using the Heart Graft protocol is recommended for an optimized segmentation of the heart in presence of grafts. This protocol uses various VR presets for a better heart imaging.

Cardiac Transparency protocol

The Cardiac Transparency protocol displays a VR view containing:• the left chambers,• the right chambers,• the VR tree (i.e. aorta + coronaries),• the heart muscle,• the surrounding bones.


10The Cardiac Transparency protocol uses an automatic segmentation algorithm to separate heart cavities from cardiac muscle and bones. An insufficient contrast in the heart cavities can lead the algorithm to display only a transparency view of the heart with Tree VR and bones.For some exams, the identification of the heart cavities may fail. After computation, perform a visual check of the different volumes and correct them using the Autoselect tool (Add/Remove vessels).

In the Automatic Vessel Selection panel:• click (Display Vessels) to grow coronary vessels (refer to the Tree VR protocol),• click (Adjust) to refine vessel display via the Automatic Selection panel,• click (Next) to bring back the cardiac chambers and myocardium. If modifications to the model are necessary,

highlight the object that requires editing then edit it.• Drag the sliders of the 3D Visualization panel to adjust the transparency of:

• the left chambers,• the right chambers,• the VR tree,• the heart muscle, • the surrounding bones.

CAUTION


10Other ProtocolsCardIQ Volume Rendering protocols with names that begin with "Cardiac" will load and display the complete exam volume using volume rendering, without segmentation.

Volume Rendering

In brief, volume rendering is used to display 3D objects by allocating different levels of "opacity" to different voxel values. Additional information can be shown by using color shading, i.e., displaying different voxel value ranges in the image in different colors.The use of volume rendering takes into account that tissue density is not uniform and that the distinction between two features of different density is determined by a range of voxel values rather than by a single fixed value.An example is the display of contrast-enhanced vessels with typical voxel values in a range of 200 to 450 HU (but some as low as 100 HU) embedded in soft tissue with typical voxel values in a range of -100 to +100 HU.


10By setting the opacity to 0% (transparent) at 0 HU and to 100% (opaque) at 200 HU, tissue below 0 HU will be displayed as fully transparent and tissue above 200 HU as fully opaque. Soft tissue above 0 HU will still be displayed as mostly transparent, vascular tissue below 200 HU still mostly as opaque. As a result, the vessels are displayed clearly separate from the surrounding tissue. Volume Rendering is well suited to separating features with such adjacent voxel value ranges because it does not rely on a fixed single threshold value to distinguish the two. By contrast, the conventional technique of thresholding combined with surface shading is much more sensitive to the threshold setting: too low a threshold and "pieces" of soft tissue start appearing around the vessels, too high a threshold and part of the vessels is no longer displayed.

PresetsThe settings of the VR presets in the CardIQ Volume Rendering protocols are primarily aimed at displaying contrast-enhanced blood within the exam, i.e., the arterial vasculature and the large volumes such as atriums, ventricles and aorta. You can adjust the settings in these presets to optimize the display.

While you can use these presets as they are, their primary purpose is to act as a starting point: after applying a preset, adjust the settings to optimize the display of the anatomical features and/or pathologies being examined.The settings you will be using may vary from exam to exam, depending both on the characteristics and quality of the acquisition data and on the particular features and pathologies in the exam.When you change any of the control settings the display is updated each time, allowing you to rapidly determine the best settings for the features you are currently examining.You can save the settings that best match your particular requirements as new custom protocols.


10You can also study features other than vasculature by using Volume Rendering settings different from those in the CardIQ VR presets.

ControlsFor a detailed description of the volume rendering controls (VR Tools in the Volume Viewer 3 control panel) refer to the Volume Viewer 3 user documentation.This section summarizes the controls and their use for cardiac imaging.In brief, there are two techniques:- Use the VR Opacity panel to set the curve type, opacity values and maximum opacity, and the VR Colors panel

to define the color style and the colors used for color shading, or:

- Use the VR Colors panel to defined one or more "attached objects". All controls for this function (opacity values, maximum opacity and color) are combined in the VR Colors panel and the VR Opacity panel is inoperative.

To display the VR Tools control panels, click on the (VR Tools) button in the Volume Viewer 3 main control panel, and select the panel in the menu. After opening one of the panels, you can move between them with the (Back|Next) buttons.The panels are displayed on top of the lower left view. You can move them by clicking and dragging on the title bar, or close and recall them as necessary via the VR Tools menu.


10VR Presets Panel

The VR Presets panel contains the controls to select VR presets, to delete/save VR presets and to switch to VR color and VR opacity panels.

The VR presets supplied with CardIQ Xpress use color shading for added contrast between anatomical features (e.g., to accentuate calcifications).

Preset list: click on icon to select

Delete/Save Preset

Close VR Tools panels

Scroll preset list

Next to Opacity/Color panel

Anatomy: menu to select VR presetfrom other anatomical categories("Cardiac" category by default)


10VR Opacity Panel

The VR Opacity panel contains the controls to set the opacity (curve type, voxel values, maximum opacity).

Select the curve type with the buttons below the Opacity control bar, then move the two diamond-shaped sliders to set the control points for the selected curve type, i.e., the voxel values of the endpoints of the curve. - The (upramp) is the most commonly used curve type. It is used in the CardIQ VR presets.- The (show range) curve type can be used to "hollow out" the vessels and blood volumes. Select a voxel

range corresponding to the outer limits of the vessels and blood volumes only, then apply a cut plane (see page 189) and rotate the 3D volume as required. This can allow you to examine some interior features.

Transparency sliders: drag slider to adjust object transparency

Delete Object

Color: color shading on or off

Close VR Tools panels Switch to Preset/Color panel

Object preview

Maximum Opacity: move thumbwheel to adjust or click up/down arrows

Curve Type buttons


10The (downramp) and (hide range) curve types have no practical application in cardiac imaging.

Two features are available to help match the opacity curve settings to the voxel values (HU numbers) in the exam:- The small red triangular cursor marker below the scale on the control bar continuously indicates the voxel

value (HU number) at the position of the 3D cursor. By moving the 3D cursor to different positions on an anatomical feature, you can rapidly assess the voxel value range that defines it.

- Whenever you move one of the sliders, all voxels with HU numbers higher than the slider setting are shown with green hatching on the baseline views.

Use the {Maximum Opacity} thumbwheel to set the opacity (in percent) of the point of maximum opacity of the selected curve.- When lowering the maximum opacity to a value below 100%, voxels in the maximum opacity range of the

curve are no longer displayed as fully opaque but as transparent to a degree determined by the maximum opacity setting. Displayed features are now built up from the contribution of several voxels along the "line of sight", and the effects of incidental high-value voxels (noise, small intervening anatomical features) on the final image are attenuated.

- The maximum opacity setting also affects the color shading. See VR Colors Panel, page 188.When saving the current setup as a new custom protocol via (Save Preset), you can include the automatic segmentation feature (see page 177) in the custom protocol by using a name for the new protocol beginning with "Heart".


10VR Colors Panel

The VR Colors panel contains the controls used to set up color shading, and also to create "objects" defined by the range of voxels corresponding to a color control point (slider).You can switch between normal and enhanced resolution images. The use of normal resolution accelerates the display of changes to the image while enhanced one improves the display of small features. Use normal resolution to set up the image, then switch to enhanced resolution to view the final result.The Partial Volume Filter function is described in detail in the Volume Viewer 3 user documentation. It has little effect on cardiac-type images and can usually be left off.


10

Color shading can be turned on or off with the (Color) button.The use of color shading allows you to differentiate features in the image defined by different voxel values within the visible voxel range. As an example, by displaying a lower range of voxel values in red and a higher range in white (as in one of the VR presets) it becomes possible to accentuate the presence of calcifications.

Color style: set style of color transition between control points to [Ramp] or [Step]

Brightness: adjust to varyoverall image brightness

Color palette: move markerto set color hue and saturation for selected color slider

Close VR Tools panels Back to Opacity/Preset panel

Color control bar: click on slider to select it, click and move slider to set color control point

Attach Object: display voxel range defined by selected color slider as separate "object"

Add/Delete Color


10The effect is more pronounced at lower maximum opacity settings: this makes "outside" voxels more transparent so that underlying features become visible.The choice of the actual colors depends on your requirements. For instance, for images to be used for presentations or documentation you may prefer "natural" colors (such as red for the blood volumes and white for calcifications and bone) while under different circumstances you may want to use contrasting "false" colors to accentuate a particular feature. The CardIQ VR presets show examples of both.Two features are available to help match the color settings to the voxel values (HU numbers) in the exam (similar to those on the opacity control bar, see previous paragraph):- The small red triangular cursor marker below the scale on the color control bar continuously indicates the

voxel value (HU number) at the position of the 3D cursor. By moving the 3D cursor to different positions on an anatomical feature, you can rapidly assess the voxel value range that defines it.

- Whenever you move one of the color sliders, all voxels with HU numbers higher than the slider setting are shown hatched on the baseline views with the color corresponding to that slider.

The Attach Object function uses a technique of defining "objects" by a range of voxel values "attached" to a color slider. This function is described in detail in the Volume Viewer 3 user documentation.For a single object the result is directly comparable to that obtained with the "show range" opacity curve mode. The difference is that the opacity curve and maximum opacity are now set up on the color control bar at the same time as the colors. The opacity control bar is inoperative if any attached objects are defined.When you define more than one object, you can adjust maximum opacity for the voxel range of each object separately.


10Other Functions

Some of the display and 3D processing tools from Volume Viewer 3 available on the 3D view may be useful in special cases.

Cut planes: you can apply a front cut or back cut plane to the 3D view. - A front cut will remove all features in front of a plane perpendicular to the line-of-sight passing through the 3D

cursor. Such a cut plane, together with appropriate rotation of the 3D volume and suitable VR settings, can for instance be used to view a 3D cross section of a region of interest.

- To select a cut plane, use the drop-down menu of the cut plane active annotation ("No cut" by default).Cut planes are a display feature only, they do not change the 3D volume.

Note: In VR "Heart" protocols (where the name of the protocol begins with "Heart"), the automatic segmentation removes external features such as sternum and ribs.

- If for any reason you use a VR protocol without automatic segmentation, the sternum and ribs tend to obstruct the display of features on anterior views. If you cannot bring a feature of interest into view by simply rotating the 3D volume, placing a front cut plane just behind the sternum on an anterior view will remove the sternum and most of the ribs without affecting the display of the cardiac region.

3D shutter: you can apply a 3D "shutter", i.e., a spherical cut plane centered on the 3D cursor, to the 3D view.- Only the part of the exam located inside the sphere is displayed.- To apply a 3D shutter, select [Shutter on Cursor] in the drop-down menu of the shutter mode active

annotation ("No VOI" by default). Use the shutter size active annotation (which appears when the shutter is present) to adjust the diameter of the sphere.The 3D shutter is a display feature only, it does not change the 3D volume.


102 CARDIAC REFORMAT BATCH PROTOCOLLaunching the Cardiac Reformat protocol automatically displays oblique views of the heart oriented along Short Axis, Long Axis and Vertical Long Axis: • Sagittal (S),• Long Axis (LA),• Vertical Long Axis (VLA),• Short Axis (SA).

Short Axis

Long Axis

Vertical Long Axis(behind panel)

Sagittal


10- Adjusting Long and Short Axis viewsThe orientations of the Short and Long Axis views are locked by default. However, you can manually correct these orientations by adjusting:• the Long Axis view in the Sagittal view,• the Short Axis view in the Long Axis view.

- Adjusting Long Axis view• Click the Long Axis button. The Sagittal view is selected and the Long Axis view is unlocked,• Page through the images in the Sagittal (upper left) viewport and find the image with the mitral valve and apex

of the heart,• Rotate the yellow line so it goes through the mitral valve and apex: the result can be seen in the Oblique (upper

right) viewport.

- Adjusting Short Axis view• Click the Short Axis button. The Long Axis view is selected and the Short Axis view is unlocked,• Position the cursor on the mitral valve on the Long Axis view,• Rotate the yellow line so it is perpendicular to the Long Axis of the left ventricle.• Click the Short Axis button again to deactivate the edit mode and to display batch icons.


10Note: The batch buttons described below are not available in the Cardiac Reformat panel of the Ejection

Fraction protocol.

Using Batch buttonsCardIQ Xpress is supplied with Batch buttons to view, save and film batch series of reformatted images aligned with the short and long axes of the heart.The Short Axis batch button is used to prescribe batch series of short axis views only.The Long Axis batch button is used to prescribe batch series of long axis views only.The Vertical Long Axis batch button is used to prescribe batch series of vertical long axis views only.These batch images can be used as input for the Function package.


10Short Axis batch • Click the Short Axis Batch button: the batch lines are automatically displayed perpendicular to the long axis

of the heart.

Batch lines

Batch center.Click and drag to move batchBatch rotation points (red dots)

Click and drag to rotate batch


10Modify, film and/or save batchThe Batch Film panel that is now displayed is identical to that used elsewhere in Volume Viewer 3. Refer to the Volume Viewer 3 user documentation for a full description of the controls and functions in this panel.

The Short Axis protocol uses the following default batch setup:- Parallel oblique batch of 25 views with 4.0mm spacing,- Field of view 20.0cm,- The views are 4.0mm thick slices (MPVR), using Average rendering mode,- Output mode is defaulted to Save.

• To view the batch images, select (Preview).This sets up a movie loop of the batch images. You can run through the loop, or pause and step to examine individual images.

• To modify any of the default settings, select (Modify).The use of the Modify Batch panel is described in full in the Volume Viewer 3 user documentation. The basic features are:

• To change any of the numerical parameters, click inside the corresponding field to select it,, delete the existing value using the <BackSpace> or <Del> key, and type in the new value. Confirm with <Enter>.

• The number of views and the spacing between views are linked: changing one automatically changes the other, so that the depth of the "stack" stays the same.

To change the depth of the batch "stack", click and drag on the red arrows that are displayed on the first and last batch line.


10• To view the modified batch before accepting it, select (Preview).• When you are satisfied with the changes, select (Accept). To cancel the changes, select (Cancel). Either

command returns you to the Batch Film panel.

• To save the batch images as a new series on the workstation hard disk, select (Save).

Note: The default output mode for the protocol is Save. To film the batch images, select (Modify) and change the mode to [Film] in the Output pull-out menu.To both film and save the batch at the same time, set the mode to [Film/Save].Select (Accept) to close the panel. The legend of the button in the Batch Film panel will reflect the new setting.


10Long Axis batch• Click the Long Axis batch button: the batch lines are automatically displayed parallel with the oblique long

axis plane.

Modify, film and/or save batch• Check and if necessary modify the resulting batch, then save and/or film it, as described for the Short Axis

batch above (page 194).

Batch lines

Batch center.Click and drag to move batch

Batch rotation points (red dots)Click and drag to rotate batch


10Vertical Long Axis batch • Click the Vertical Long Axis Batch button: the batch lines are automatically displayed parallel with the long

axis.

Modify, film and/or save batch• Check and if necessary modify the resulting batch, then save and/or film it, as described for the Short Axis

batch (page 194).

Batch lines

Batch center.Click and drag to move batch

Batch rotation points (red dots)Click and drag to rotate batch


10Using the Double Oblique ProtocolThe CardIQ Xpress Short Axis and Short Long Axis protocols allow you to prescribe, view and save/film batches of reformatted short and long axis views. You may want to use the same techniques to view a particular location in a cardiac exam, without needing to film or save an entire batch.In such cases, use the Double Oblique protocol from the Additional Guides protocol category, using the procedure described below.

Note: You can save individual images at any time, using [Save Image] in the on-view menus or the <S> key on the keyboard. The format of the saved images will be either Rfmt (reformat) or SSave (screen save) depending on the setting of the Film/Save Options in the Volume Viewer 3 Filming Tools menu.

• Select (Additional Guides) in the main Volume Viewer 3 control panel, then select [Double Oblique] in the protocol panel. Initially, an oblique, axial, sagittal and coronal view is displayed. The coronal view is hidden below the protocol panel, but you can move the panel by clicking and dragging on its title bar, if required.

• Click on the sagittal view to select it.• On the sagittal view, use the image location active annotation, or the slider of the {review controller} (with

Card. mode off), to move through the images, and display the image showing the mitral valve and the apex of the heart.

• On the sagittal view, move and rotate the oblique reference line (solid yellow), so that it passes through the mitral valve and the apex. You move the reference line by moving the 3D cursor, and rotate the line by clicking and dragging anywhere on it except at the location of the 3D cursor.The oblique view shows the corresponding long axis image.


10Second oblique• Select (Next).

A second oblique view is now displayed. The first oblique view is selected automatically, and displays the reference line for the second oblique.

Short axis views• Rotate the reference line on the first oblique view until it is perpendicular to the long axis.

The second oblique view now shows a short axis view.• Move the 3D cursor to examine different locations.Two-chamber long axis views• Rotate the reference line on the first oblique view until it is parallel to the long axis.

The second oblique view now shows a two-chamber long axis view.• Move the 3D cursor to examine different locations.Four-chamber long axis views• Re-select the sagittal view by clicking on it. If necessary return the 3D cursor to the initial position (see above).

The first oblique view now shows the four-chamber long axis view.• Move the 3D cursor on the sagittal view to examine different locations in planes parallel to the long axis.

Note: When you re-select the sagittal view, the setup of the second oblique view is canceled and both oblique views show the same image. To again display a short axis or two-chamber long axis view on the second oblique view, re-select the first oblique view and re-align the reference line on that view.


103 PHASE REGISTRATION

OverviewThe Phase Registration protocol is a protocol used with multiphase datasets, which allows the user to align a ventricle or a coronary vessel, using images taken from different phases to create a new series dataset. From time to time, cardiac images can show some misregistration artifacts, due to irregular heart motions, EKG imperfections or other factors. To correct these defects, this protocol allows you to replace misregistered slices by ones taken in other phases. Registration will in particular allow you to obtain a better image quality of the coronary vessel before using a Vessel Analysis protocol, or when creating a Cine Loop.The protocol takes you through the following steps:- Preparation of the registration,- Registration of the structure,- Saving of the result of the registration.

The protocol steps are described in more detail below.


10Step 1 - Prepare Registration

• Select the reference phase using the Phase active annotation at the top of the views to page through all the loaded phases.

• Use the oblique tool (yellow lines on the top right view) or the cursor to position the oblique view so as to be able to properly view the artifacts to be corrected. (For more information on how to position the oblique view, refer to Volume Viewer 3 User Guide, GE document ref. 5169457-100, Chapter 8 “Reformatting”, Section 2 “Oblique Reformatting”).

• Select (Next).


10Step 2 - Phase Registration

The green lines displayed on the views represent groups of slices. The percentage displayed on the right of the lines correspond to the phase associated with the group located beneath the line. Each group is composed of slices which were reconstructed during the same heart cycle and at the same cardiac phase. Therefore misregistration artifacts appear only between groups of slices rather than within a group. To start with, all groups of slices belong to the same phase. If you want a better vision of the views, you can hide them by deselecting the (Identify Slices) button. • Select the registration mode, (Between Lines) or (Around Cursor), depending on wether you want to use

the red lines or the cursor to define the section to be registered.

Between Lines Around Cursor


10 • If you have selected Between Lines, move the red lines to select a region (group of slices) to be registered.

You can then require either an Automatic or a Manual Registration. You can use both modes one after the other, and thus manually adjust an automatically registered image.

With an Automatic registration, the software will look at all the surrounding phases and replace the misregistered slices by others taken in other phases. In this mode, the result of the registration is computed to globally minimize misregistration for the whole heart region comprised within the selected slices.

In a Manual registration, click on the (Previous Phase) or (Next Phase button). The software will replace all the slices included between the two lines by those of the phase you have requested. You will then visually decide whether the image is registered. Repeat the changes as often as needed.

When performing a Manual registration, the result of the registration can only be visualized on a small part of the volume (the axial, oblique and coronal views for the current location). Due to several factors, such as variation in heart movements or the fact that some cardiac regions may be at rest at different phase locations, this operation can result in new misregistration artifacts in other parts of the volume. Therefore, when using this mode, carefully study the entire volume in all rotations, before saving, networking or filming any images created using phase registration, so as to check that the registration has not degraded image quality.

Note: An automatic registration is performed on the whole heart region comprised within the selected slices. For the same reasons as above, the result might not be optimal for the slices which are currently visualized. If you want to optimize a specific region, you can use the Around Cursor mode. If you, want to optimize a specific vessel branch using Phase Registration, you can also use the Register option in the Step 3 of the Vessel Analysis protocols (refer to Chapter 5 - Vessel Analysis - Procedures ).

CAUTION


10• If you have selected Around Cursor, place the cursor in the middle of the area you want to register. Click on

the (Automatic Registration) button. The software will then try to minimize the misregistration artifacts in the region surrounding the cursor by looking at slices in other phase locations. Only slices located up to 2cm from the current cursor position will be modified.

In the Around Cursor mode, the software looks only at the misregistration in a small region surrounding the cursor. Due to several factors, such as variation in heart movements or the fact that some cardiac regions may be at rest at different phase locations, this operation can result in new misregistration artifacts in other parts of the volume. Therefore, when using this mode, carefully study the entire volume in all rotations, before saving, networking or filming any images created using phase registration, so as to check that the registration has not degraded image quality.

Annotations on Axial ViewsSome annotations specific to the registration are displayed on the views:- The name of the phase is displayed at the top of the views (percentage).

Note: Whenever wanted, the user can use the Phase active annotation to change the current phase and start registering another phase. All the phases can be registered independently. On the Active Annotation pull down menu, the name of the registered phases is followed by (Reg).

- The (Reg) annotation next to the name of the current phase shows that at least one slice of the volume has been registered.

- Reg. Ph: 70% on the left of the view: original phase of a registered slice (on the Axial view only).

CAUTION


10At this level you can close the Registration protocol and apply to the volume any protocol you need or any Volume Viewer 3 tool. They will then be applied to the registered volume(s).The (Reg) annotation remains to inform the user that the current volume has been registered. If you have, for example, registered different phases you can create a Movie.• Select (Undo) to cancel the last performed operation for the current phase.• Select (Restore Original Volume) when you are not satisfied with the result of the registration and want to

start it again from scratch.• Select (Next) if you want to save the registration for later session.

Step 3 - Saving ResultsThe Save Registration panel is now displayed. It will allow you to save the registered volume in the Patient List as a new 3D object. Only the current phase is saved, with its registration and all the existing annotations, which means that you will later be able to apply any single-phase protocol on this “modified” volume.• Select (Save Registered Volume).• A pop-up window is displayed requesting you to enter the name of the new object. This name will appear in the

Description of the new object in the Patient List.• Select (OK).


104 CARDIAC SPECIFIC REVIEW FUNCTIONS

Layout PresetsNot all available layout presets and protocols may be shown in the Review Steps window. To see the full list of layout presets and protocols, click on the Options/More button.For more information on the Layout Presets, refer to the Volume Viewer 3 User Manual, Chapter 6 “Display and Controls”, Section 2 “Panel Controls”.

Customizing the default layout preset [Pro only]

Note: The factory default layout for vessel analysis protocols is AVA Layout 3. Two additional layouts are available in the Review Steps window: AVA Layout 1 and AVA Layout 2.

For every AVA protocol, you have the ability to select any other layout from the Layout Presets list (or to create a new layout), and to save it as default. The (Save Default Layout) button on the Display Preferences panel (available in Display Tools > Preferences) will allow you to save the current layout so as to display it automatically when launching the same AVA protocol.

Using the Oblique Review layout presetThe Oblique Review layout preset allows you to define manually double oblique cross section snake views of the vessels: orientate the first oblique from the axial view (first screen upper left view port) and the second oblique cross section snake views from the first oblique view (first screen upper right viewport).


10Using the 2D Cardiac Review scenarioThe 2D Cardiac Review scenario allows you to review the exam in reference orientations for cardiac vessels study.The available layouts are the following:• Great Vessels: allows you to see the ostium and the beginning of the LAD and of the RCA.• Grafts: allows you to see the mammary veins.• RCA/LAD/CIRC Reviews: allow you to study the coronary arteries from the ostium to the distality part.• Oblique Review: as described above, allows you to focus on the area of interest of a vessel without tracking.


103DPOS Active AnnotationA new active annotation line is provided in several of the CardIQ Xpress protocols to display LAO/RAO, CRA/CAU angles on 3D views and oblique views. It is automatically updated each time the orientation of the view is modified. LAO and RAO stand for Left Anterior Oblique and Right Anterior Oblique. They indicate a rotation from an initial anterior view in the left and right direction, respectively.CRA and CAU stand for Cranial and Caudal. They indicate an additional rotation in the up-down or down-up direction, respectively.It also allows the user to manually modify the orientation of the view, by changing the LAO or CRA active angle value with the mouse buttons.In several CardIQ Xpress protocols, clicking the 3DPOS active annotation text (LAO/RAO, CRA/CAU) displays a list of predefined angles presets in a drop down menu. Clicking these angles presets allows the user to automatically tilt the views in typical cardiac cath orientations (without changing the view type or the layout). The orientations are shown in terms of LAO/RAO and CRA/CAU angles, e.g., “60 LAO” or “30 LAO 30 CRA”.

Cardiac AnnotationSome specific annotations are displayed on the left-hand side of axial images. These annotations are linked to each view and change when you page through the views.- Average heart rate - BPM: cardiac rythm (in beats per minute)- SSEG (Snapshot Segment), SSB (Snapshot Burst), SEGM (non gated reconstruction) : used cardiac

reconstruction algorithms- 330 ms: temporal resolution.


10Cardiac FiltersTo apply a filter reducing the banding artifacts in a cardiac dataset, click the active annotation and select a filter.By default, no filters are applied : the annotation is set to ‘(No filt.)’. The filters are described in the table below.

When a cardiac filter is active, all views showing the filtered volume have the string “(Card 1)” (resp. 2 or 3) appended to the phase annotation.

Note: The current filter remains active when switching to another protocol.

Note: [Pro only] If a cardiac filter is applied, statistics for Color Identification will not be available. You must remove the cardiac filter in order to display statistics to ensure accuracy.

Note: Cardiac filters can not be used in conjunction with phase registration.

Table 1: Cardiac Filters

Filter Action

Card 1 Replaces the first slice of each band with an interpolated slice

Card 2 Replaces the last slice of each band with an interpolated slice

Card 3 Replaces both the first and last slices of each band with an interpolated slice


10Color Identification [Pro only]The Color Identification function enables you to depict the plaque on all reformatted views by depositing two points.Check the instructions below for a detailed description:• Click the (Color Identification) button (available in the Verification of the Results panel),• Click on view to deposit the first point,• Click on view to deposit a second point: a color ramp is automatically applied around the segment defined by

the two deposited points. It is displayed in all reformatted views as well as curved and oblique views,• Click the plaque annotations (start pos., end pos. and diameter) to modify the length and the diameter of the

plaque,• Click the plaque name annotation to display a drop-down menu allowing you to send the plaque to the Report,

to delete the plaque, or to select another deposited plaque.A discrete color ramp with four segments is displayed on the left hand side of each view (except Lumen). The color ramp defines a color for a range of voxel values.

Note: To adjust the color ramp, refer to the Color Ramp paragraph below.

Note: Statistics will not be displayed if cardiac filters are applied.


10Color ROIDepositing a 3D color ROI on view will allow you closer local study.Click the 3D Color ROI button and click the image of interest: a rectangular graphic will display representing the area of interest in three dimensions on axial, sagittal and coronal views.Click the green box at the center and drag to reposition the ROI. Click the green boxes at the corners to resize.

Note: Size and position must be checked on the orthogonal views.A default color ramp will display at the left border of the image. The color ramp defines a color for a range of voxel values. To adjust the color ramp, refer to the Color Ramp paragraph below.

Color RampOnce a color plaque or color ROI is deposited, it is possible to see volumetric statistics and to adjust the color ramp displayed on the left of the viewport.Click the color ramp: the Color Map Table panel containing three tabs is displayed.The Statistics tab displays a table containing the volumetric statistics of each range of voxels corresponding to a color. The third column shows for each color the percentage of colorized volume inside the region of interest. If several color structures have been deposited on the same exam, they can be compared in the same table.The Configuration tab enables you to configure the color ramp. You can:• Add/Remove color segments. By default, a new segment has no color.• Change the color of a segment by clicking the color cell. A range of colors will display allowing you to select a

new color or to switch to “Black and White”.


10Note: If you select “Black and White”, the voxels belonging to this segment will not be colorized but will display

their own grey level values. It allows you to create a gap between two color regions.• Enter a name for a segment to personalize the color ramp.• Adjust the limits of a segment.

Note: These limits can also be adjusted by middle mouse clicking and dragging to left or right the red annotations on the ramp.

Note: Color segments are adjacent : the maximum value for a segment is the minimum value for the next segment.

• Switch the color ramp from steps to continuous mode. In continuous mode, the color ramp is smoothed to better detect repartition of grey values within each segment.

Note: Volumetric statistics are not available in continuous mode.• Click the Presets tab once the color ramp is adjusted.

The Presets tab allows you to:• Save the current color ramp as a preset.• Remove the last applied preset.• Apply a different preset.


10Other Volume Viewer 3 FunctionsSince CardIQ Xpress is part of the Volume Viewer 3 application, all standard and optional Volume Viewer 3 tools, view types, etc. (such as Reformat and Navigator, and 3D processing, display and filming tools) are fully available at all times. These functions are described in the Volume Viewer 3 user documentation.Certain separate applications that can be used for cardiac image analysis (such as the SmartScore and Function packages) can be invoked directly from the Cardiac category protocol panel.For the use of such applications, refer to their specific user documentation.


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CHAPTER 11 - MOVIE CREATION

In CardIQ Xpress, all the Volume Viewer 3 filming tools are available. However, the software offers specific additional features.

With multi-phase datasets, the user will be able to create movies of a beating heart with the Movie function. For more information regarding the Movie function, refer to section Movie of the Volume Viewer 3 User Guide, GE Ref. 5169457-100.

The Batch Loop function offers the possibility of creating a batch film focused on a specific vessel branch (see section below).

All the animations can be saved in the Patient List or exported.


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1 BATCH LOOPIn addition to the Batch Loop features of Volume Viewer 3, CardIQ Xpress offers the possibility of creating and saving batch loops focused on a specific vessel branch.These loops are created exactly in the same way as standard Volume Viewer 3 loops (refer to the Volume Viewer 3 user documentation). However, CardIQ Xpress offers new choices of batch loops:• Loops on Curved or Lumen views that occur in rotation around the vessel branch. To create this type of loops, specify a different angle for the (First View) and the (Last View) and possibly adjust the step (by acting on the Angle active annotation).• Loops on Oblique views, for X-section, L-section and Best-L-section modes that occur along the vessel branch. To create this type of loop, specify the (First View) and the (Last View) linear position along the vessel (by acting on the LP active annotation or using the Vertical Slider of the Review Controller) and possibly adjust the step.


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CHAPTER 12 - OUTPUT

The regular AW Basic Display and Volume Viewer 3 tools are available within CardIQ Xpress to save and film images.

The CardIQ Vessel Analysis protocols automatically generate a report that can be filmed and saved as required. To fill in a Report with any CardIQ Xpress Pro protocol, refer to Section 2 in this chapter.

You should take due care that saved or filmed images always include the necessary annotations.


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1 SAVING AND FILMING IMAGESUse the regular AW and Volume Viewer 3 tools to save and film images at any time during image review and analysis with CardIQ Xpress.

• To save individual images, use either the <S> key on the keyboard or the [Save Image] menu item in the on-view menus.

• To assemble a set of images that can be saved and filmed as required, use the Filmer.• To save and/or film a batch of regularly spaced oblique images, or 3D images rotated in steps, use the Volume

Viewer 3 Batch Film function.This Batch Film function is also included in the Cardiac Reformat protocol to save and/or film batch series of short and long axis views. See Chapter 10 - Image Review.

Reformatted views (2D oblique and baseline views) are saved either in Rfmt or SSave format. Select the desired format using (Filming Tools) > [Film/Save Options] in the control panel.

Refer to the AW Basic Display and Volume Viewer 3 user documentation.


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2 FILLING IN A REPORT [PRO]Every protocol of the CardIQ Xpress package includes a Reporting feature allowing you to fill in and save a Report.To fill in a report, open the Report panel by clicking (Report) in the main panel and (Data Input).The Report panel is made of three types of data entered manually by the user:• [Pre-Exam tab] Pre-Exam data,• [Findings tab] Exam Analysis data,• [Conclusion tab] Post-Exam data.

Pre-Exam DataClick the Pre-Exam tab in the Report panel and fill in the following areas:• Family and Patient history,• Exam procedure,• Patient follow up,• Patient form.


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Exam Analysis dataThe Findings tab allows you to:• Create/Delete/Navigate through findings,• Add information, measurements and comments related to a finding,• Add images to a finding.

There are four types of findings:• Plaque, Stent, Bypass or Anomalous,• Normal,• Ancillary or Other,• Aneurysm.Depending on the type of finding you create, the finding information area to fill in will be different.

Sending images, measurements and ROI's manually to the ReportClick the (Send to Report) button on the Review Controller to send the image to the Report. An icon for this image is displayed in the Findings Image area. Clicking this icon will display a panel allowing you to rename, delete, preview this image and add comment.Right click a measurement/ROI on-view annotation and select (Send to Report) in the drop down menu to send this measurement/ROI to the Report. It will attach the image with its associated measurement/ROI to the current finding and display the measurement/ROI value in the Findings Measurement area. Clicking the image icon will


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display a panel allowing you to rename, delete or preview this image, to add comment and to display measurement/ROI statistics.

Sending automatic images to the ReportDuring the protocol workflow, you are enabled to send some data to the Report directly via the protocol panels.The (Send to Report) button on the step 1 protocol panel will automatically:• Create a finding with the name of the current protocol,• Send the upper left viewport in six different orientations to the Report in the Automatic Images area.The (Report Finding) button on the step 3 of vessel analysis protocol panel will allow you to select a finding type. Once it is selected, a finding will be created in the Report with the name of the branch and the name of the current finding.

Vessel Analysis summary imagesWhen using CardIQ Vessel Analysis, the protocols automatically generate a report that contains the measurements performed during the analysis and the associated images. This report can be filmed and saved as required. See Chapter 5 - Vessel Analysis - Procedures.In the course of a vessel analysis you can use the same tools as during review (see page 218) to film and save images separately, but you can also "queue" images that will be added to the report.To add images to the "report queue":• Click with the right mouse button on the image to be saved, to open the on-view menu.• Select [Queue Report Image] in the menu.


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The queued images are added automatically at the end of the report when it is saved or filmed.

Post-Exam dataClick the Conclusion tab in the Report panel to display Post-Exam data:• General images (images sent to the report when no findings have been created),• Conclusion selector,• Conclusion.The conclusion selector allows you to select how the conclusion will appear in the Conclusion area. To customize the report conclusion, click the (Report) button in the main panel, click (Configure) and follow the panel instructions.

Saving the ReportThe (Save Report) button displayed at the bottom of all Report panels will create in the AW database a new series containing a Structured Report DICOM file (SR). All images are saved in the database separately as SCPT or Reformatted series. As these images are linked to the SR file, removing them from the database will remove them from the final Report.This Report can be edited and modified in PDF or HTML with the Reporting Tool software application. For more information regarding this application, refer to the Reporting Tool User Guide, GE ref. 5135929-100.


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3 ANNOTATIONSReformatted views (2D oblique and baseline views) can be saved either in Rfmt or SSave format.

When using the Rfmt format, system information (patient name, location, etc.) is saved together with the image and recovered by other viewing applications as required. Only user annotations (text, graphics) become part of the image.

When using the SSave format, the saved images are of type SCPT (secondary captures). On such images all annotations become part of the saved image and cannot be modified by another viewing application at a later stage.Using this format, all annotations (such as system annotations, text annotations, etc.) that are displayed on the screen will also appear on the filmed or saved images. In the vessel analysis reports, extra annotations that identify the images are also added automatically by the software.If the annotations on the screen have been turned off (see the Volume Viewer 3 user documentation) they will not be present on the filmed or saved images either.

Although images without annotation may be suitable for teaching purposes, diagnosis should not be performed with such images.CAUTION


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While working on an exam, you can hide the patient name on the views for increased confidentiality. If you have done so, make sure to show the patient name again on the views BEFORE filming or saving images for diagnostic purposes. To do this, refer to the Volume Viewer 3 User Guide.

When filming or saving images for diagnostic purposes, always make sure the patient name is displayed on all views.CAUTION


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4 SAVE STATEThe Save State allows you to save the current layout, the current protocol panel and the performed segmentations listed below.

LayoutLoading a Save State will display the same layout as the one displayed when the Save State was performed.

SegmentationsThe Save State allows you to save the following segmentations if previously computed:• Tree VR• Angiographic View• Heart• Heart GraftRecalling them (when Save State is loaded) will not take additional computation time.


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Protocol panelsThe current protocol panel will be restored when reloading a Save State:Cardiac Reformat• main Cardiac Reformat panel and the orientations will be restoredEjection Fraction• current protocol panel for each step will be restoredHeart, Heart Graft, Cardiac• current protocol panel will be restoredCardiac Transparency• current protocol panel and segmentations will be restoredVessel Analysis protocols (Left Coronary, Right Coronary, Coronary, Tree VR, Angiographic View)• Definition of Section to Analyze panel will be restored if tracking has not been performed before the Save State• Verification of the Results panel will be restored if tracking has been performed before the Save State

Vessel Analysis protocols / Save Tracking• multiphase centerline will be restored• editions of the centerline will be restored if the centerline was edited

Save State will not restore the editions of the contours. Contours and quantifications will be recomputed.


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Appendix 1 - Landmark Examples

To obtain satisfactory identification (tracking) of the coronary vessels, you need to mark the points at the right location in the vessels.

This appendix illustrates some examples of suitable points for the left and right coronary arteries in a typical exam.

These images are not intended as anatomical references but only as examples of how to place the points on the images.NOTICE


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1 LEFT CORONARY ARTERIES3D MIP view, with the following points marked in the left coronary arteries:-Start of section (Start)-Left main artery (LMA)-Left anterior descending artery (LAD)-First diagonal artery (1st Diag., branching off the left

anterior descending artery)-Left circumflex artery (LCA)-Left marginal branch (LMB, branching off the

circumflex artery)

The illustrations on the following pages show the corresponding axial views.

Note: The 3D MIP view is oriented the same way as the axial views (inferior-to-superior view) but uses a smaller DFOV.


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Start of section (Start)

The start-of-section point should be placed inside the vessel near its origin, not in the aorta, to avoid vessel identification errors.


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Left main artery (LMA)


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Left anterior descending artery (LAD)


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First diagonal artery (1st Diag.)


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Left circumflex artery (LCA)


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Left marginal branch (LMB)


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2 RIGHT CORONARY ARTERIES3D MIP view, with the following points marked in the right coronary arteries:-Start of section (Start)-Distal point in the right coronary artery (RCA)-Posterior descending artery (PDA)

The illustrations on the following pages show the corresponding axial views.

Note: The 3D MIP view is oriented the same way as the axial views (inferior-to-superior view) but uses a smaller DFOV.


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Start of section (Start)

The start-of-section point should be placed inside the vessel near its origin, not in the aorta, to avoid vessel identification errors.


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Distal point in the right coronary artery (RCA)


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Posterior descending artery (PDA)


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Posterior Lateral Branch (PLB)


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GLOSSARY

Note: Words in italics refer to terms defined elsewhere in the Glossary.For general terms concerning the workstation and the AW Basic Display software, also refer to the Glossary in the AW Basic Display Operator Manual.

3D Model - The representation of the 3D (three-dimensional) image data in the workstation computer memory. 3D models can be saved, archived and networked.

Active Annotation - A system annotation on a view that can be modified by the user to control certain viewing parameters (e.g., window width and level), either by adjusting a numerical value, or by selecting an item from a drop-down menu. Active annotations are displayed in red.

Algorithm - A step-by-step process used to solve a problem. In the CardIQ Vessel Analysis protocols, this refers in particular to the process used to identify (track) and quantify the vessel section to be analyzed.

Annotation - Generally, workstation-supplied text which accompanies an image when it is displayed on-screen, describing when and how that image was acquired, with what parameters. Also, text and measurement information added on a view by the user.

Artefact - Feature in an image resulting either from the initial data acquisition or subsequent computer processing that does not correspond to a real feature in the original anatomical structure. Also see Partial Volume Effect.

Baseline view - A basic axial, coronal or sagittal view, aligned parallel to the main axes of the RAS coordinate system.

Browser - The panel used in the AW 3.1 Basic Display application to select available images for display and manipulation. Referred to as the Patient List in AW 4.0 or later.


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CT (Computed Tomography) - Process of deriving anatomical information by computer synthesis of X-ray data, acquired by means of a CT scanner in the form of parallel "slices".

DFOV (Display Field Of View) - The real dimensions of a view (width and height) with reference to the RAS coordinates.

DICOM - Abbreviation for Digital Imaging and Communications in Medicine. Standard for the formatting and exchange of medical images and associated information.

Display matrix - The number of pixels in a displayed image, expressed in terms of number per axis - e.g., 512 x 512.

Exam - In CT, all images made from data taken of a patient after entering a particular scan cycle.

Field of View (Acquisition FOV) - The area of the anatomy being imaged, usually expressed in centimeters. FOV image size is a function of the acquisition matrix times the pixel size.

HU (Hounsfield Unit) - Scale unit denoting the density within a voxel in a CT data set.

Image - In this document the term "image" is used to designate the part of the exam data being processed and displayed on the workstation screen. Depending on the display settings, a view (q.v.) can display an entire image, or part of it (zoom).

Image Display Area - During use of a viewing application, the portion of the screen where images are displayed.

Measurement Annotation - A user annotation on a view that shows the result of a measurement.

MPVR (Multi-Projection Volume Reconstruction) - A technique that allows you to define and display a "thick" slice that encompasses a feature of interest, instead of using baseline and oblique views that represent slices that are only one voxel thick.


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On-view menu - Menu displayed either on a view or on a particular feature of a view such as a user annotation by pressing the right mouse button.

Partial Volume Effect - The appearance of voxels with intermediate values at the interface (separating surface) between two tissue types with clearly distinct and different densities, where these voxels do not correspond to a real feature in the original anatomical structure.

Patient List - The panel used in the AW Basic Display application to select available images for display and manipulation. Referred to as the Browser in AW 3.1.

Pixel - Abbreviation for "picture element", the smallest distinguishable component of a digital image display.

RAS - Abbreviation for Right/Anterior/Superior. Designation for the patient-linked coordinate system used in CT data sets.

Rendering - Techniques used to represent a three-dimensional object on a two-dimensional surface.

Review Controller - On-screen tool to rapidly move through the images of an exam using a slider and arrow buttons or display them in cine mode. Also allows to mark images of interest ("bookmarks"), then return rapidly to a marked image. The slider can be used to set slice thickness in MPVR mode.

Roam - Another term for "Scroll".

Scroll - An on-view control, used to view a particular part of an image by moving the image around within a view, when the image has been enlarged ("zoomed") and hence the complete image no longer fits in the view.

System Annotation - An annotation on a view added by the system software, containing data concerning the displayed image. Certain system annotations can be active, i.e., they can be modified by the user.


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Text Annotation - A user annotation on a view containing text. Text annotations can be used to add comments, or to add a legend to an anatomical feature on a view.

Title Bar - A bar at the top of a window that provides information about that window, and also allows you to move the window to a different position on the screen by clicking and dragging on it with the mouse.

Toggle - The act of switching a function from on to off, or off to on, with a single mouse click of the pointer on the function's button. Toggle buttons usually appear within windows and other monitor screen areas, but some keys on the keyboard may also provide toggle functions.

User Annotation - An annotation on a view added by the user, containing either text or the result of a measurement.

Vessel Tree - In the context of CardIQ Xpress, refers to the coronary arteries and all connected vessels, that can be displayed separate from the surrounding tissue and large blood volumes by the Tree VR protocol.

View - Part of the workstation screen, used to display image data. The view area of the CardIQ Xpress screen normally contains four views. A view can display an entire image, or part of it (zoom).

View Area - During use of a viewing application, the portion of the screen(s) where images are displayed. The view area normally contains four views, but a single view can be enlarged so as to take up the entire view area.

VOI (Volume Of Interest) - In CardIQ Xpress, the volume displayed in the 3D view that contains the selected section of the vessel to be analyzed.

Volume Rendering - Rendering technique that links voxel values to varying degrees of opacity. Used in the Volume Rendering protocols to display anatomical features (vasculature in particular) separate from the surrounding tissue.

Voxel - Abbreviation for “volume element,” the basic element in a CT data set.


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Window (1) - Describes the range of pixel values that are assigned a shade of grey. Narrow windows offer greater resolution and contrast of anatomy having similar densities. It also helps you find the values for anatomy in which you are interested. See window width and level.

Window (2) - "Window" is also the term used for an on-screen graphical tool used to display information.

Window Width and Level (W/L) - In this context, "window" refers to the range of pixel values within the image data, that is assigned a shade of grey for display. "Level" refers to the center value. "Width" refers to the range of pixel values displayed around this central level (the value corresponds to twice the number of intensities above and below the currently set level).

The adjustment is marginally similar to adjusting brightness and contrast controls: a narrow window (low width) translates to a high contrast of the display, and similarly a low level translates to a high value of brightness.See the AW Basic Display Operator Manual for more details.


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REVISION HISTORYREV DATE REASON FOR CHANGE PAGES

1 September 2006 M3 release 2482 January 2007 M4 release 2483 April 2007 Post M4 release 248

NUMBER SIZE REVISION5180542-100TPH 3Letter A5


Documents

CardIQ Xpress Pro