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imagination at work

GE Healthcare

T H E M A G A Z I N E O F M R • FA L L 2 0 0 6

3.0T: SAR Management Without Compromise

MR ECHO – A New Approach in Cardiac Imaging

Improving Breast DiagnosisUsing High-Resolution MRI

Produce High-ResolutionMR Images DespitePatient Movement

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GE Healthcare News

Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

MR History of Innovation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Calendar of Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Mayo Clinic and GE Healthcare Announce Collaboration to Develop Clinical 3.0T Body MRI . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Space Saving MR Technology for Community Hospitals and Imaging Centers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Unprecedented Resolution and Speed for MR Imaging of Even the Most Difficult Patients . . . . . . . . . . . . . . . . . . . . . . . . . 8

Strongest Portfolio of Applications Along with BreakthroughTechnology on New 3.0T Premium MR Scanner. . . . . . . . . . . . . 9

New Clinical Performance Available in GE’s “XV” Line of MR Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 A GE Healthcare MR publication • Fall 2006

T A B L E O F C O N T E N T S

GE News: Space Saving MR Technologyfor Community Hospitals and Imaging CentersPage 8

Clinical Value: Musculoskeletal MRI Clinical Cases with Signa HD 1.5T and CartiGramPage 10

Technical Innovation: 3.0T MR Imaging:SAR Management without Compromise Page 48

Clinical Value

Musculoskeletal MRI Clinical Cases with Signa HD 1.5T and CartiGram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

High Definition Abdominal MRI . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Acquisition Technique Breathes New Life into Abdominal MR Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Imaging of the Hippocampus . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Producing High-Resolution MR Images Despite Patient Movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Signa HD with PROPELLER HD Provides Efficiency and Image Quality Enhancements. . . . . . . . . . . . . . . . . . . . . . . . 28

Improving Breast Diagnosis Using High-Resolution MRI. . . . 30

Breast MR Provides Pioneering Clinic with Excellent ROI While Enhancing Patient Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Diffusion Tensor Imaging Delivers Crucial Information . . . . . 40

A New Imaging Approach in Cardiac MRI Reveals Physiologic Abnormality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

MR Evaluation of Patent Foramen Ovale (PFO) . . . . . . . . . . . . 46

© 2006 General Electric Company, doing business as GE Healthcare. All rights reserved. The copyright, trademarks, trade names and other intellectual property rights subsisting in or used in connection with and related to this publication are, the property of GE Healthcare unless otherwise specified. Reproduction in any form is forbidden without prior written permission from GE Healthcare.

LIMITATION OF LIABILITY: The information in this magazine is intended as a general presentation of the content included herein. While every effort is made by the publishers and editorial board to see that no inaccurate or misleading data, opinion or statements occur, GE cannot accept responsibility for the completeness, currency or accuracy of the information supplied or for any opinion expressed. Nothing in this magazine should be used to diagnose or treat any disease or condition. Readers are advised to consult a healthcare professional with any questions. Products mentioned in the magazine may be subject to government regulation and may not be available in all locations. Nothing in this magazine constitutes an offer to sell any product or service.

TOC.qxd 9/11/06 2:29 PM Page 2

The information contained in this document is current as of publication of the magazine.

Beyond the Scan: The GE HealthcareMR Masters Series Helps CliniciansAchieve Maximum Results Page 65

Technical Innovation

3.0T MR Imaging: SAR Management without Compromise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

PROPELLER HD Gives a New Spin on the Old Problem of Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Functional Magnetic Resonance Imaging: Tools for the Clinical Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Peripheral Vascular MR Angiography . . . . . . . . . . . . . . . . . . . . . 58

New Non-Invasive Treatment Option for Uterine Fibroids Using Signa 1.5T and MR Guided Focused Ultrasound . . . . . 60

Complete Brain and Spine Imaging Without Coil Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Beyond the Scan

The GE Healthcare MR Masters Series Helps Clinicians Achieve Maximum Results . . . . . . . . . . . . . . . . . . . . . 65

Medicare Reimbursement Update . . . . . . . . . . . . . . . . . . . . . . . . 67

A Tale of Two Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Publications Team:David Handler,General Manager, MR Strategic Global Marketing

Renee Adelle Stasiewicz,Global Marketing Communications Manager,Diagnostic Imaging Modalities

Mary Beth Massat,Editorial Consultant

GE Contributors:Dave Piontek,Marketing Communications Manager, MR

Joanna Jobson,MR Strategic Marketing Programs Manager

Simone Hammer, Marketing Communications MRI, Europe

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G E H E A LT H C A R E N E W S W E L C O M E

1979

First whole-body 1.5Tsuperconducting

magnet

1983

First MR surface coil

1984

Detachable MR table

Superconductive shim technology

1988

Actively shielded gradient coils

First Phase Contrast MR Angiography

Fast Spin Echo

1989

Phased array coils

1991

SIGNA SP intraoperative MR

MR guided Focused Ultrasound prototype

1994

Echo PlanarImaging

1996

K4 low cryogen boil-off magnet

technology

MR History of Innovation Since the 1970s, GE was on the forefront of innovation in MR for clinical use. This list represents just some examples of GE contribution to industry firsts.

Accelerating the translation of technological advances intoclinical practice is the embodiment of GE Healthcare’s visionfor transforming healthcare. And, together we are makinggreat advancements.

Consider for a moment that 94 percent (or 15 out of 16) of the nation’s top hospitals, as determined by U.S. News &World Report’s 2005 Survey of America’s Best Hospitals, arescanning with GE MR systems. The prevalence of GE’s 1.5TMRI is widespread, with these systems representing greaterthan 60 percent of the installed base for all brands in the US.And, the migration of 3.0T MR systems from the researchsetting to everyday clinical use has been swift. In fact, 85 percent of Signa 3.0T scanners are purchased for use within the clinical setting today.

In the last two years, MRI has reached a new level with the introduction of the new Signa® HD product family. At the same time, a streamlined system has been designedfor the community hospital – one that requires 30 percentless space and 40 percent less cost to operate than othercomparable systems yet provides many of the same clinical applications as our 1.5T and 3.0T systems.

GE has listened to MR clinicians and technologists andresponded with a comprehensive breadth of powerful clinical applications. Within this first issue of Signa PULSE,you’ll find articles on five exclusive MR applications enabledby our Signa HD systems:

Welcome

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G E H E A LT H C A R E N E W SW E L C O M E

1998

Interactive Cardiac Imaging

1999

3.0T clinical magnet for head imaging

2001

High field open MRI scanner

3.0T whole body clinical magnet

2002

Acoustic Noise Reduction

Diffusion TensorImaging

2003

PROPELLER HD

VIBRANT

TRICKS

BrainWave clinical fMRI

Developed 32-channelwhole-body MRI

2004

MR guided FocusedUltrasound

MR Echo real-time cardiac imaging

FiberTrak

2005-2006

GEM parallel imaging

BREASE breast spectroscopy

Integrated HD Head-Neck-Spine coil

• PROPELLER HD™ for high-quality brain imaging overcomingmotion artifacts

• MR Echo™ for real-time heart imaging without breath holding or ECG gating

• VIBRANT® for bilateral breast imaging in a single exam

• TRICKS™ for MR angiography of the legs

• LAVA™ for making outstanding abdominal MR imaging easier

The advancements also extend to therapeutic radiology.Today, GE remains the only company to answer this challengeby offering MR guided focused ultrasound, available on the GE Signa HDx 1.5T. Along with our business partner, InSightec,we will continue to explore the boundaries of non-invasiveMR-guided therapy with thermal ablation.

Plus, collaborations with leading institutions like the recentlyannounced Mayo Clinic/GE alliance should further expandMR capabilities and gain excellent clinical focus to furtherbring forth technological advances even more expeditiously.

Tomorrow, GE will continue to drive the Re-imagination of its MRI systems – technology, applications and performance.As the leader in MRI, GE Healthcare is committed to helpingclinicians redefine MR imaging.

This publication provides a forum to share our customers’vision and our vision that MRI can provide tremendouslyvaluable information to promote early health in peoplearound the world.

Enjoy,

John Chiminski, Vice President and General ManagerGE Healthcare’s Global MR Business

John Chiminski

News_1 Letter from John.qxd 9/11/06 2:18 PM Page 5



G E H E A LT H C A R E N E W S E V E N T S

Calendar of EventsGE looks forward to seeing you at the following events.

Conference Dates Conference Center City and State Country Web linkor Hotel or Provence

World Congress Sept. 2-6 Fira Gran Via M2 Barcelona Spain www.escardio.orgof Cardiology

24th International Sept. 12 -16 Cape Town International Cape Town South Africa www.isr2006.co.zaCongress of Radiology Convention Center (CTICC)(ICR 2006)

European Society for Sept. 21-23 Gromada Conference Center Warsaw Poland www.esmrmb.orgMR in Medicine and Biology

Joint CTMRI-U/SP Oct 5-7 Manila Hotel Manila Philippines www.philippineradiology.orgConvention “Experience”

MR Imaging of Oct 5-7 First Hill Diagnostic Imaging Seattle, WA USA www.firsthill.comBreast Cancer

Advanced Cross-Sectional Oct 6-7 Harvard Medical School Boston, MA USA cme.hms.harvard.eduPediatric Imaging: U/S, CT and MRI

Mount Sinai Update 2006: Oct 12-15 Hilton Hotel New York, NY USA www.ryalsmeet.comBrain, Spine, Neurovascular & ENT Imaging

5th Annual Breast MRI Oct 12-14 Wynn Hotel Las Vegas, NV USA www.radiologycme.stanford.eduin Your Facility

Global Symposium on Oct 15-16 Wynn Hotel Las Vegas, NV USA www.radiologycme.stanford.eduClinical High Field MRI

Journees Francaises Oct 18-22 CNIT Paris la Defense Paris France www.eventseye.comde Radiologie (French (21-25)Radiology Congress)

British Society of Interventional Nov 1-3 Scottish Exhibition and Glasgow UK www.bsir.orgRadiology (BSIR) Conference Centre

MEDICA Nov 15-18 Dusseldorf Trade Fair Centre Dusseldorf Germany www.medica.de

Musculoskeletal Nov 21-22 BIR Portland Place, London UK www.bir.org.ukSpine & Non-Spine

RSNA Nov 26-Dec 1 McCormick Place Chicago, IL USA www.rsna.orgConvention Center

ESI: MRI in Clinical Practice Feb 18-23 Snowmass Snowmass Village, CO USA www.edusymp.comConference Center

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7A GE Healthcare MR publication • Fall 2006

G E H E A LT H C A R E N E W SM A Y O C O L L A B O R A T I O N

Mayo Clinic and GE Healthcare announced an ambitious program for clinical development of high field magnetic resonance imaging (MRI) of the body. This collaboration,announced at the 14th Annual Scientific Meeting andExhibition of the International Society for Magnetic Resonancein Medicine, is designed to help realize the full potential of 3.0T (Tesla) MR systems as a diagnostic tool, particularly for the abdomen, heart, breast and musculoskeletal system.

Mayo Clinic and GE Healthcare Announce Collaboration to Develop Clinical 3.0T Body MRIFocus is to Realize Full Potential of Body Imaging to Improve Patient Care

with us for the benefit of patients. Both Mayo and GE Healthcarebring exceptional resources and enthusiasm to the developmentof clinical applications for this exciting new technology.”

GE will be installing at Mayo Clinic a state-of-the-art 3.0T MRsystem and collaborating through a team of scientists and engineers to help develop new imaging protocols forhigh-field MRI.

“This announcement marks a significant milestone in our long collaboration with Mayo Clinic, one of the most widelyrespected healthcare institutions in the world,” said John Chiminski, vice president and general manager of GE Healthcare’s global MR business. “By working together,we will enjoy an excellent clinical focus by bringing all of ourprototypes to one place for the most rigorous clinical scrutinyand rapid feedback.

Through our collaboration with Mayo Clinic, we’re investing in the future of healthcare,” Chiminski added. “This collaboration embodies our vision of transforming healthcareby accelerating the translation of technological advancesinto clinical practice.”

About Mayo Clinic

Mayo Clinic is a not-for-profit organization dedicated to thediagnosis and treatment of complex patient illness in anenvironment in which physicians from every medical specialtywork together to meet patient needs. Mayo Clinic providescomprehensive clinic and hospital services at its sites inRochester, Minn., Jacksonville, Fla., and Scottsdale/Phoenix,Ariz. Mayo Clinic integrates clinical practice, education andresearch with an unwavering focus on meeting patientneeds. More than 2,500 Mayo Clinic physicians and scientistsand 42,000 allied health staff treat more than half a millionpeople each year. �

“Accurate and earlydiagnosis is the criticalforerunner to effectivemedical treatment,which is why Mayo isfocusing on improvingthe diagnostic capabilitiesof advanced MR imaging.”

The collaboration, through the Body MRI AdvancedDevelopment Unit at Mayo Clinic, Rochester, Minnesota, willdevelop and apply the most clinically viable techniques for 3.0T MR imaging, the highest strength magnetic field in clinicaluse. It will also allow Mayo Clinic patients to benefit from all that MRI technology can offer in accurately diagnosingconditions such as breast and prostate cancer, liver diseaseand coronary artery disease.

“Accurate and early diagnosis is the critical forerunner toeffective medical treatment, which is why Mayo is focusing on improving the diagnostic capabilities of advanced MRimaging,” said Kimberly K. Amrami, M.D., head of the bodyMR imaging practice at Mayo Clinic in Rochester. “We arehappy that GE has agreed to a new level of collaboration

Kimberly K. Amrami, M.D.

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The new Signa® HDe 1.5T builds on GE Healthcare’sproven high-definition (HD) platform while also

delivering lower operating costs and reducedoverall siting space. As a result, GE’s Signa HDe 1.5T delivers the HD line of clinical applications to hospitals and imaging centers as well as provides a convenient solution to bring 1.5T MR services onsite in places not previously possible.

Dr. Takayuki Masui, Chief of Radiology,recently added the new Signa HDe

1.5T to the radiology departmentat Seirei Hamamatsu

General Hospital inHamamatsu, Japan.

“We were previously at full patient capacity with ourthree existing GE 1.5T systems and needed to add afourth scanner to accommodate the increased numberof patient referrals,” said Masui. “Now, having SignaHDe 1.5T, we have been able to expand our capacityto accommodate all of the referrals in our community.Scheduling patients is also much easier since thecapability of this machine is comparable to that of theother three for the majority of procedures.”

The Signa HDe 1.5T is built on GE’s exclusive HD MRplatform and can be installed in the same physicallocation as 0.5T MR systems with minimal constructionexpense. Installation time has been reduced to onlyone week and has a 30 percent smaller footprint thana typical 1.5T system. �


G E H E A LT H C A R E N E W S N E W P R O D U C T S

The Signa® HDx 1.5T premium scannerfrom GE Healthcare lets radiologists seecritical areas of MR images previouslycompromised by challenging patientconditions. It provides the ultimatecapabilities and eliminates past trade-offs and helps radiologists to be morecertain when diagnosing even thetoughest cases through GE-exclusiveapplications.

New technologies introduced with GE’sSigna HDx 1.5T system include: the “XV”line of premium clinical applications –VIBRANT-XV™, TRICKS-XV™ and LAVA-XV™; ultra-fast image reconstructionthrough the new XVRE recon engine;breakthrough advancements in parallelimaging algorithms; new acquisition

LAVA-XV

strategies; and, the new interlocking,Signa high-density coil system (head-neck-spine).

Signa HDx 1.5T scanners utilize GE’s exclusive, new Signa high-densityperipheral vascular lower leg array,which provides images of the lower legand foot vessels with unprecedenteddefinition, according to Dr. Steven D. Wolff,Director of Cardiovascular MRI and CT,Cardiovascular Research Foundationand Chief of Cardiovascular MRI, LenoxHill Hospital.

“More than half of patients with diabeteshave inadequate characterization of lower-leg vasculature, even with traditional MR angiography (MRA) techniques,” said Wolff. “The Signahigh-density lower leg array is easy

to use and is comfortable for the patient.It provides full coverage from the kneesto the toes, and has enough signal tomake great MR angiograms.” �

Unprecedented Resolution and Speed for MR Imaging of Even the Most Difficult Patients

Space Saving MR Technology for Community Hospitals and Imaging Centers

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Continuing GE Healthcare’s leadership in the development of 3.0T MR technology, the newSigna® HDx 3.0T is GE’s latest MR innovation that opens further growth for clinical use at this Tesla strength.

New technologies introduced in GE’s Signa HDx3.0T include: the “XV” line of premium clinicalapplications – VIBRANT-XV™, TRICKS-XV™ andLAVA-XV™; ultra-fast image reconstructionthrough the new XVRE recon engine; breakthroughadvancements in parallel imaging algorithms; thenew acquisition strategies; and, the new interlocking,Signa high-density coil system (head-neck-spine),which provides the convenience of an interlockingthree-part system without any compromise to image quality.

Signa HDx 3.0T scanners utilize GE’s exclusiveSigna high-density coils, including the new Signa high-density breast coil, which combines the industry’s highest signal to noise ratio, multi-dimensional parallel imaging and biopsy capability. GE also introduced the only 3.0T high- density hybrid extremity coil that provides ultra high-resolution extremity imaging.

“We invested in GE’s 3.0T technology because it provides the finest image detail available,” said Marc D. Shapiro, M.D., of NeuroskeletalImaging, a strategic collaborator with GE on new,breakthrough MR imaging technologies. “With theresolution of the Signa 3.0T, we will be able todetect smaller and more subtle abnormalities.” �

Along with the recent launch of GE Healthcare’s line of HDx MR systems –the Signa® HDx 1.5T and Signa HDx 3.0T –GE also introduced the new “XV” releasesof its signature line of MR applications.New clinical performance is now available on the following applications:

• VIBRANT-XV™ provides bilateral breastimaging in a single exam withouttrading off spatial or temporal resolution, as well as introduces newbreast spectroscopy functionality;

• TRICKS-XV™ enables dynamic fullcoverage MR angiography (MRA),even in high flow circumstances by scanning eight times faster thanconventional MRA techniques;

• LAVA-XV™ enables, for the first time,whole abdomen exams in a singlebreath-hold.

TRICKS-XVVIBRANT-XV

GE offers PROPELLER™ HD, one of thecompany’s leading MR applications.PROPELLER HD yields high-quality brainimaging that is extremely resistant tomotion artifacts, especially useful incases where patients are difficult to

image due to movement, includingParkinson’s patients who suffer from uncontrollable patient motion and children who do not respond to sedation. �

New Clinical Performance Available in GE’s “XV” Line of MR Applications

Strongest Portfolio of Applications Along with Breakthrough Technology on New 3.0T Premium MR Scanner

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Musculoskeletal MRIClinical Cases with Signa HD 1.5T andCartiGram

Laveran Hospital (Marseilles, France) is a 200-bed militaryhospital that consists of a large population of young patientswith sports-related injuries. Since the installation of the newGE Signa® HD 1.5T with a Signa HD Knee Array, the imagequality has dramatically increased, giving the radiologistseven more diagnostic confidence. High-Definition (HD) MRenables the radiologist to better analyze the morphology of various joint structures, whereas the CartiGram™ T2 studyassists in the early evaluation of cartilage diseases and provides the orthopedic surgeon with the information needed to determine an appropriate course of treatment.

Knee

The Signa HD Knee Array features an innovative hybrid technology along with an ergonomic design that togetherprovide patient comfort. These features include:

• A split-top opening enables the coil to pivot and slide laterally on its base. The handle bar locks the top andsecures the bottom on the base.

• PURE coil signal intensity correction is based on coil intensity profile calibration and requires no additional scan or processing time.

• Quadrature Birdcage is used for RF power transmissionand as the receive coil during the Prescan and PURE calibration. Key feature is a “twisted” birdcage for a moreuniform RF deposition within the excitation volume.

• Phased Array elements (8) are used for signal receptionand when tapered to the knee anatomy provides exceptional signal-to-noise performance.


C L I N I C A L V A L U E M U S C U L O S K E L E T A L – C A R T I G R A M

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The hybrid technology of the transmit and receive coil brings outstanding chemical fat saturation across the entire imaging volume. In addition, the transmit and receive operation offers two key advantages:

• Reduced specific absorption rate (SAR) or RF power,enabling higher throughput for more slices per TR;

• No wraparound from the other knee or popliteal flow artifacts from swapping phase and frequency.

According to Professor J.F. Briant, Head of the RadiologyDepartment, Laveran Hospital, “Thanks to the Signa HD KneeCoil, the image quality of our musculoskeletal examinationshas improved considerably.

The HD Knee Array provides enough signal-to-noise ratio(SNR) to allow us to acquire very thin slices with high resolutionwhile maintaining high contrast. These two image quality criteria provide a better morphological analysis and overallsignal in each of the joint structures: the menisci, ligaments,cartilage, sub-chondral bone and soft tissue.”

Case 1: High-resolution Imaging with Signa HD

40-year old male suffering from knee pain after medical history of algodystrophy secondary to a synovectomy.

Coronal T1416x320 matrix 3mm thickness, 16 slices 3min 00s scan time

Sagittal PD 512x384 matrix 3mm thickness, 24 slices 3min 29s scan time

Linear intra-meniscal hypersignal: meniscopathy without fissure


Coronal PD and Fat Sat 512x320 matrix 3mm thickness, 20 slices 3min 51s scan time

Fatty focal areas following algodystrophy

Coronal T1 416x320 matrix 3mm thickness, 16 slices3min 00s scan time


Small area of sub-chondral cystic necrosis

Coronal PD and Fat Sat 512x320 matrix 3mm thickness, 20 slices 3min 51s scan time

Axial PD and Fat Sat 512x320 matrix 2.6mm thickness, 20 slices 3min 35s scan time

Small area of sub-chondral necrosis of the medial femoral condyle


C L I N I C A L V A L U EM U S C U L O S K E L E T A L – C A R T I G R A M

Technology Leadership




C L I N I C A L V A L U E M U S C U L O S K E L E T A L – C A R T I G R A M

Sagittal PD FSE 512x384 matrix 2.4mm thickness, 24 slices 3min 29s scan time

Sagittal T2 Mapping 256x224 matrix 3mm thickness, 8 echoes, 13 slices 6min 01s scan time

Cartilage thinning of the anterior section of the medialfemoral condyle (arrow), also presenting signal discrepanciesin favor of oedema

Case 2: Cartilage Imaging and CartiGram

24-year old female competition volleyball player, presentingwith pain in flexion following ACL-PCL ligament surgery.

Colored map (A) showing T2s from 20ms in red to 80ms in blue, with calculatedT2 values from ROIs. ROI #2 green curve (B) shows the 8-echo signal pattern and the red curve shows the calculated monoexponential fit .

Focal strain area in the supero-medial portion of the patellar cartilage (arrow)

CartiGram

CartiGram is a non-invasive imaging method to assess articular cartilage integrity. It allows clinicians to better seecollagen fiber network loss or degradation that translatesinto focal T2 increase.

CartiGram is based on a multi-echo pulse sequence derivedfrom the existing FSE-XL that can create up to 8 echoes per single acquisition. Typically, not more than eight echoesare acquired, due to the cartilage short T2 relaxation times.CartiGram then calculates a mono-exponential pixel-by-pixelfit from the real signal decay curve. By providing informationneeded to help determine the appropriate course of treat-ment, CartiGram can reduce unnecessary arthroscopy andprovide the required images to monitor the effectiveness oftreatment noninvasively, eliminating the need for a “second-look” biopsy.

“The new Signa HD Knee Array allows us to produce, in clinical routine, high-quality examinations of the knee. The access to the exploration of the cartilage, thanks to the T2-Mapping sequence, offers a new perspective to diagnoseand treat chondropaties at an early stage,” said Prof. Briant.

CartiGram is an optional feature available only on the SignaHDx platform. The following clinical case was acquired with a prototype version tested by Hospital Laveran. �

A B




C L I N I C A L V A L U EA B D O M I N A L – L A V A

Recent advances in MRI technology have greatly impacted abdominal MR applications.Improvements in hardware have boosted signal to noise by concentrating a largenumber of coils in the field of view (FOV). Improvements in software have takenadvantage of this enhancement to increase resolution, reduce scan time, add tissue contrast and help ensure clinical consistency.

Recent progress in image quality arises, directly or indirectly, from the simultaneousacquisition of the MR signal by many small coils. The expression “high-density coil”describes this concept well. Only high-density coils yield the extra signal to noise,the solid foundation from which GE Healthcare offers a comprehensive solutionfor abdominal MRI applications.

While a high-density body coil lays the required firm foundation for abdominal MR,GE’s Parallel Imaging technique – ASSET™ – constitutes the central pillar of thestructure. ASSET adds a new degree of freedom to the scan protocols. With echotrains cut short, Single Shot Fast Spin Echo (SS-FSE) and Single Shot Echo PlanarImaging (SS-EPI) show less blurring artifacts and less susceptibility distortions. As aresult, the clinical status of SS-FSE has evolved from a mere fast localizer to a robusttechnique insensitive to patient motion and further, to the accepted standard inthe study of abdominal ducts. On the other hand, ASSET serves as an accelerationdevice, able to change signal-to-noise ratio (SNR) into speed or spatial resolution.

When scan time doesn’t match a reasonable breath-hold, ASSET can reduce itwith uncompromised resolution and salvage the examination of an uncooperativeor elderly patient. More importantly, ASSET is an integral part of a new techniqueused for liver and pancreas with contrast uptake.

This technique, known as LAVA™, combines contrast-enhanced, multi-phase imagingof the abdomen with high resolution, large coverage and uniform fat suppression.In one breath-hold, LAVA acquires a stack of overlapping thin slices with high in-plane resolution. The usual protocol repeats this acquisition three or more times.In this way, LAVA produces images of the arterial, portal and venous phases that

High DefinitionAbdominal MRISigna HD 1.5T and LAVA

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C L I N I C A L V A L U E A B D O M I N A L – L A V A

not only precisely depict anatomy and contrast uptake, butalso contain vascular information, easily revealed by a MIPpost-processing. A single multi-phase LAVA acquisition, withone injection, provides more information than two traditionalscans. LAVA enables abdominal imaging with the information-rich contrast of MR and the simplicity of CT.

Though the dynamic study is central to abdominal MR, thereis also a need for a simple and fast abdominal survey of vasculature and soft tissue. Fat Sat FIESTA can efficientlyaccomplish this, even without contrast media. This steady-state 2D sequence, with a very short TR and a hybrid T2/T1tissue contrast, presents several clear advantages comparedwith previous ultra-fast GRE sequences. It is of considerablevalue when a motion-insensitive method is needed. Oftenincluded in today’s standard abdominal protocol, Fat SatFIESTA is particularly helpful in assessing the portal and systemic venous system and the bowels.

High-density coils, parallel imaging and better pulsesequences have combined to offer a non-invasive, specific andreproducible diagnostic tool. Even as technology continuesevolving, the clinical cases depicted in this article supportthe clear point that MR technology has already built a solidplatform for the expansion of abdominal imaging.

Dynamic contrast enhanced T1 weighted acquisition is central to the abdominal examination. LAVA acquisition: Post-processing using Volume Rendering and Movie Tool in Volume Viewer.

Liver perfusion

Arterial perfusion

Portal systemic

Liver parenchyma

Arterial phase

Portal phase

Liver veins





Liver

An MR liver examination must guide the therapeutic strategyand/or preoperative planning with a clear depiction of thesegmental anatomy and its relationship with vascular andbiliary structures.

Case

Hepatocellular carcinoma (arrow) with tumor invasion of theportal vein. Comparison between the FSPGR Fat Sat aftercontrast media injection and the Fat Sat FIESTA sequencewithout contrast.

Fat Sat FIESTA:Sl. thickness: 5 mm 0.7 sec / slice

Fast-Spoiled GRE with Fat Sat: Post-contrast media injection Sl. thickness: 5 mm 24 slices Acq. Time: 23 sec

Fast-SPGR with Fat Sat Fat Sat FIESTA

“The Fat Sat FIESTA acquisition is a very useful sequence for assessingthe venous system in the abdomen. The sequence is now part of ourliver protocol, in particular of use in displaying the portal venous system.The sequence is very robust and the images are of high aesthetic quality.This sequence is also of considerable value when a motion-insensitivemethod is needed.”

Pr. D. Weishaupt, M.D. – University Hospital of Zurich, Switzerland

“The LAVA images look like MDCT images, butwith the soft tissue of MR!”






Biliary System

MR Cholangio-Pancreatography (MRCP) is a frequently used,non-invasive alternative to the classic endoscopic retrogradetechniques. Either in breath-hold with SS-FSE, or triggered by respiration with FR-FSE, MRCP can depict the entire pancreatobiliary tract with high spatial resolution. As anemerging technique, LAVA in combination with liver-specificcontrast agents, which are partially excreted through the biliary system, can produce a functional MRCP study withvery interesting results such as in the case shown below.

Case

Investigation of a communication between a hepatic cysticlesion and the main bile duct after contrast agent (MnDPDP)administration: type I Choledochal cyst (Todani classification)of the common hepatic duct.

Respiratory-triggered FR-FSE with Fat Sat: Sl. thickness: 6 mm 24 slices Acq. time proportional to respiratory cycle

LAVA: 2 hours after contrast agent administration Sl. thickness: 3.2 mm (ov-1.6) Acq. time: 18 sec

“The LAVA sequence is very useful for assessing small abnormalitieswithin the biliary tract. High in-plane-resolution and the use of thin slicesimages allow a high accuracy in the evaluation of vascular structures.The ability to depict enhancement of the common bile duct wall provides an advantage for MRA using LAVA, as opposed to MDCT.”

Dr. M. Zins – St Joseph Hospital, Paris, France

FR-FSE Fat Sat after contrast agent administration

LAVA after contrast agent administration





Pancreas

An MR cholangiographic examination must depict the pancreatic and biliary ductal anatomy and delineate theextension of masses and inflammatory processes to theadjacent soft tissues. A pancreas MR examination is a comprehensive study.

Case

Chronic pancreatitis of the tail of the pancreas (▲) and pseudo-cystic lesion in the isthmus of the pancreas (▲).Notice the intra-hepatic portal thrombosis (▲).

LAVA: Axial acquisition Sl. thickness: 3.2 mm (ov-1.6) Acq. time: 24 sec

FIESTA Fat Sat:Sl. thickness: 6 mm Matrix: 224x256 0.7 sec / slice

2D MRCP: Sl. thickness: 20 mm Matrix: 512x320

LAVA oblique reformationLAVA curved reformation 2D MRCP

LAVA VR LAVA Min IP

FS FIESTA FS FIESTA





Bowel

The excellent contrast resolution of MRI, combined with negative intraluminal contrast agents (such as water or ironoxides) and intravenous gadolinium, seems very promising forthe evaluation of the gastrointestinal tract. MR enteroclysis,which combines functional and morphologic information,offers cross-sectional imaging multiplanar capabilities.Breathing-independent T2 or T2/T1 weighted images,acquired respectively with SSFSE or FIESTA pulse sequences,provide an excellent depiction of the anatomy with the possibility to monitor filling during enteroclysis. LAVAsequence is used after contrast to assess enhancing inflammatory or malignant processes involving the bowel.

2D FIESTADynamic thick slab 2D SSFSE 2D FIESTA

LAVA: Native atrophic kidneys

LAVA: tubular nephrographic phase – Transplant kidney

LAVA: MIP from Subtracted images

Kidneys

MRI plays a significant role in the imaging of the kidneysbecause of its high spatial and contrast resolution and itsability to assess the vascular supply. In particular, MRI helpsreduce complications in the case of renal donation whenlaparoscopic nephrectomy is considered.

Case

63 year-old male with kidney transplant. Parenchymal perfusion defects at the upper and lower poles.

LAVA: Sl. thickness: 3 mm (ov-1.5) Acq. time: 25 sec

“In a single breath-hold, the LAVA sequence may be used for assessmentof the kidneys and arteries.”


Case

27 year-old patient with two adjacent previous surgicalanastomoses (O) that look like possible stenoses. The slabSSFSE pulse sequence is used to monitor filling during enteroclysis. The FIESTA technique demonstrates there is no wall thickening.

2D SSFSE:Coronal acquisitionMatrix: 256x256 Sl. thickness: 10 mm

2D FIESTA: Coronal acquisitionSl. thickness: 6 mm Matrix: 192x288 (512 interpolated)Acq. time: 1 sec / slice





Conclusion

(by) Pr. C. A. Cuénod European Hospital Georges Pompidou, Paris, France

Undoubtedly, abdominal and cardiac MRI are the topicswhere MRI experienced the most striking progress during thelast few years. This is mostly due to advancements in phasedarray coil technology and parallel imaging strategies.

For years, radiologists have been conscious of the tremendouspotential of MR contrast studies to characterize tissue.However, poor spatial resolution, motion artifacts and longacquisition times have constrained the spread of abdominaland thoracic applications in clinical routine. We have beeneagerly waiting for the technological progress that is at ourdisposal today.

New pulse sequences have expanded the scope of applications for abdominal MRI and have radically changedour diagnostic strategies.

• The Fast Recovery FSE (driven equilibrium) sequence givesa very high T2 weighing with reduced TR, allowing shorteracquisition time.

• The 3D T1 weighted gradient echo sequence with optimizedfat suppression (LAVA) fulfills at last the need to acquiredynamic images during the arterial and the portal phasesafter injection with high in-plane and through-plane spatialresolution. This sequence takes full advantages of the parallel imaging technique. The benefits in abdominal MRI are multiple and we probably do not yet perceive all its potentials.

In addition to liver imaging, the LAVA sequence makes it possible to consider imaging the pancreas as well as thedigestive tract. When using gut relaxant drugs, the fastacquisition almost freezes the bowel loops. It may help in theevaluation of the lesion’s activity and becomes the routineway to follow Crohn’s patients, avoiding the irradiation risksinduced by repetitive X-rays and CT examinations, especiallyin young patients.

The balanced gradient echo sequence FIESTA, initially developed for neuro and cardiac imaging, finds new applications in abdominal imaging.

Excellent in displaying water-filled areas such as cysts or bile and pancreatic ducts and digestive tract, FIESTA is alsovery sensitive for visualizing vessels. The exquisite dynamicimaging of the bowels, or MR enteroclysis, and other, lessexplored indications clearly indicate that the future place of FIESTA in the diagnostic arsenal is still evolving.

Finally these various improvements yield images with a spatial resolution near those of Volumetric CT, but with a much higher contrast and with a very large variety of contrasts. We can forecast that MRI in abdominal imagingwill be used more for its high sensitivity and for its absenceof irradiation. �

Acknowledgment

GE Healthcare expresses thanks to the following persons for theircontribution to the creation of this article, and for their long standingcollaboration in the clinical evaluations:

Pr. C.A. Cuénod, European Hospital Georges Pompidou, Paris, France

Pr. D. Lomas, University Hospital of Cambridge, UK

Dr. V. Martinez De Vega, Clinica Rosario, Madrid, Spain

Pr. D. Régent, Dr. V. Laurent, University Hospital of Nancy, France

Pr. D. Weishaupt, University Hospital of Zurich, Switzerland

Dr. M. Zins, St Joseph Hospital, Paris, France




C L I N I C A L V A L U E A B D O M I N A L – L A V A - X V

Statistics prove that out of every ten abdominal MR exams,one is rendered inconclusive either by motion artifact orinadequate resolution. To combat this problem, GE Healthcaredeveloped LAVA™, a 3D FastSPGR plus fat suppression acquisition technique. LAVA provides multi-phase abdominal imaging with enhanced fat suppression.

The advantages of LAVA include:

• It is 25 percent faster than conventional acquisition techniques, meaning shorter breath-holds for patients

• It has 25 percent higher spatial resolution for enhancedimage quality

• It provides 25 percent more anatomical coverage.

LAVA Provides Better 3D T1 Imaging

Because LAVA enables liver imaging in patients who havetrouble holding their breath, it is radically changing the wayabdominal MR imaging is performed.

With LAVA comes a new fat suppression technique calledsegmented SPECIAL, which calculates the optimum “on the fly” TI based on the number of slices and resolution.

LAVA enhances the performance of ASSET™, an accelerationtechnique, by a factor of 2.5 on 1.5T systems and 3.0 on 3.0Tsystems. With LAVA, RF pulses are optimized for shorterTR/TE, and the datasets can be used for enhanced multi-planar reformatting as well.

Among the many advantages LAVA presents in imaging of the liver and adjacent structures is the ability to captureearly arterial and early venous phases and late venousphases with high resolution and full organ coverage.

LAVA Imaging with Dual Arterial Phase

The speed of LAVA allows clinicians to perform Dual ArterialPhase imaging in a single breath-hold. Early and late arterialphase in the same breath-hold eliminates misregistrationand enables subtraction of phases one and two.

Clinical Experience with LAVA

Case 1

Jeffrey C. Weinreb, M.D., FACR, professor, DiagnosticRadiology at Yale University School of Medicine, uses LAVA-XV with GE’s Signa® HDx 3.0T MR system. Prior to usingLAVA-XV, Dr. Weinreb’s experience with abdominal imagingwas typically unreliable and limited. “When we had a case,we would hope that we’d get a high-quality, diagnosticstudy.” It was not uncommon for a percentage of abdominalstudies to be sub-optimal or non-diagnostic.

Prior to using LAVA-XV, abdominal imaging did not fulfill Dr. Weinreb’s highest expectations. Today, he is very pleasedwith the reliability and quality of abdominal images resultingfrom his use of LAVA-XV. “It has given us flexibility so we canstill get great diagnostic quality studies even in patients who may not be able to cooperate with breath-holding,” Dr. Weinreb added.

Dr. Weinreb uses LAVA-XV for virtually all abdominal applications.The benefits are obvious. “We are making better diagnoseswith a shorter scan time and we don’t have to repeat examsbecause of non-diagnostic quality images.”

ASSET, when used in conjunction with LAVA-XV, helps cutdown the imaging time. Dr. Weinreb has acquired very credibleimages in patients with an eight-second breath-hold.

Acquisition Technique Breathes NewLife into Abdominal MR Imaging

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C L I N I C A L V A L U EA B D O M I N A L – L A V A - X V

SPECIAL is a uniform fat suppression technique that improves the image qualityand Dr. Weinreb’s ability to interpret those images.

LAVA-XV with dual arterial phase has not yet been systematically studied by Dr. Weinreb. “The good news is that we can do it, however,” he said, “there are some indications in the literature that it can be beneficial for identifying andcharacterizing some types of liver tumors but we don’t have enough experience at this time to validate it .”

In many cases, MRI is now the final answer, so the patient does not have to endureadditional studies.” Essentially, prior to using LAVA-XV, Dr. Weinreb explained thatmany clinicians didn’t have faith in abdominal MRI studies to provide the neededanswer. “LAVA-XV is largely responsible for that impression change,” and a byproductof that has been an increase in referrals for abdominal MR studies, he added.

61 year old male with colon mets

44 year old male with cirrhosis

Jeffrey C. Weinreb, M.D.





Patient with diffuse liver metastases from lung cancer

Russell Low, M.D.

Case 2

For Russell Low, M.D., radiologist at Sharp Children’s Hospital (San Diego, CA), 30 percent of his practice is body MR imaging. “We currently have about the same volume of body as adult neuro, brain and spine studies; that’s almostunheard of,” Dr. Low said.

Initially installed by GE in 1991 as a long bore 4x scanner, the system was recentlyupgraded to an eight-channel Signa HDx 1.5T MR. “This system just runs and runs,and produces fabulous images,” Dr. Low added. With 15 years experience in developing clinical applications in body imaging, Dr. Low has found his Signa HDx 1.5T to be a valuable tool.

With the upgrade to Signa HDx, Dr. Low immediately began to use LAVA and foundit particularly useful for 3D dynamic gadolinium-enhanced abdominal imaging.“LAVA has certainly added to what we can do with 3D imaging. We have switchedall our dynamic post-contrast imaging to LAVA. This is a fabulous sequence thatproduces the sharpest image quality and the most homogenous images of anysequence available today.”

Dr. Low uses the SPECIAL fat suppression technique for nearly all abdomen studies,including hepatic and extrahepatic imaging. By using the 3D sequence and SPECIAL,Dr. Low can now acquire thinner slices. “The real difference with these gadolinium-enhanced LAVA images is their outstanding image quality. Before, I could acquirethin 3D slice sections but the image quality was lacking and inconsistent. On mostMR systems, 2D gradient-echo images are inherently sharper and show bettercontrast than 3D gradient-echo images. But with LAVA, I cannot tell the 2D and 3D gradient-echo images apart, and that is impressive.”

From Dr. Low’s perspective, options like ASSET should be standard practice in theindustry. “The next challenge is to see how far we can push acceleration factors,beyond the current practice of 2. Can we use acceleration factors of 3, 4, 5 or 6?What is the upper boundary that maintains image quality while increasing speedwith greater acceleration factors? We still must define the perfect balance.

Currently, our GE HD MR scanner produces consistently very good LAVA imageswith very sharp detail and great contrast,” he added. �




C L I N I C A L V A L U EN E U R O – P R O P E L L E R H D

Abstract

This case shows an epileptic patient with a tumor in the hippocampus of the left temporal lobe. The fast spin echo(FSE) T2 sequence is the sequence of choice to image thisarea. However, this sequence can suffer from patient movement. The PROPELLER™ HD T2 sequence could be the perfect solution.

The system used in this article is GE Healthcare’s Signa® HD3.0T 16-channel platform, High Density Element Brain Coil.

Introduction

Imaging lesions in the hippocampus of epileptic patients can be very difficult because of patient movement.Clinicians need very high resolution images with good tissuecontrast to see the internal structures of the hippocampus.High resolution T2 FSE images can take up to eight minutesand are very prone to motion artifact.

The PROPELLER HD T2 sequence is an excellent solution, due to its unique way of filling k-space; it can correct for patientmovement and produce images rich in signal of the hippocampus.

Patient History

This is an epileptic patient referred for scan of the temporallobes. This patient has a lesion situated in the left hippocampus.

Technique

This site uses four sequences to image the temporal lobes:oblique T2 FSE, oblique PROPELLER HD T2 FSE, oblique T2FSE FLAIR and oblique 3D fast spoiled gradient echo. For thisreport the parameters used for the T2 FSE, T2 FSE FLAIR and the T2 PROPELLER HD FSE are displayed.

FSE T2 parameters used: TE 78ms, TR 2000ms, ETL 14, BW 25 kHz, FOV 22cm, matrix 256x256, 1NEX, 5mm slice thickness.

FSE T2 FLAIR parameters used: TE 145ms, TR 11002ms, BW 31 kHz, FOV 22cm, matrix 256x224, 1NEX, 5mm slice thickness.

Imaging of the HippocampusDr Matthias Koepp, MRI Department, National Society for Epilepsy, Chalfont St Peter, London, United Kingdom

FSE T2 PROPELLER HD parameters used: TE 128ms, TR 5000ms, BW 50 kHz, FOV 22cm, matrix 512x512, 2mm slice thickness, 1.5NEX.

Findings

The high resolution PROPELLER HD images clearly showed a lesion involving the whole of the amygdala and all of thevisible part of the hippocampus.

Conclusion

Neuroradiologists at the National Society for Epilepsy believe the PROPELLER HD T2 sequence could be an excellent sequence for imaging the hippocampus and temporal lobe. �

Oblique T2 FSE Oblique T2 FLAIR

Oblique T2 PROPELLER HD Oblique T2 PROPELLER HD

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C L I N I C A L V A L U E N E U R O – P R O P E L L E R H D

Producing High-ResolutionMR Images Despite Patient Movement

The daily caseload in the Department of Radiology at the University of PittsburghMedical Center includes a substantial number of brain exams. The hospital’s diagnostic equipment includes a GE Signa® 1.5T scanner with EXCITE technology.

Solving the Problem of Patient Movement

Patient motion is a significant concern in MR imaging of the brain. “Many patientscan hold perfectly still through a complete exam without difficulty,” explainedEmanuel Kanal, M.D., Director of Magnetic Resonance Services at the University of Pittsburgh Medical Center (UPMC) Presbyterian. “Other patients can remainmotionless for some sequences but not for others. Still other patients movearound a little or a great deal and in ways that are not predictable. We also seepatients with Parkinson’s disease or patients with tremors who may be in motionconstantly throughout the exam.” Every day in their clinical caseload, as a matterof routine, Dr. Kanal will see MR images degraded mildly or substantially because of patient motion.

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PROPELLER HD

The UPMC Department of Radiology upgraded its Signa 1.5T MR scanner with PROPELLER™ HD imaging, an advancedtechnology that combines the advantages of fast spin echo(FSE) and radial data acquisition to create high-quality T2-weighted and diffusion-weighted brain images. PROPELLERHD improves contrast-to-noise ratio by 20 to 30 percent, significantly reduces the tissue-to-air and tissue-to-metal imagedistortions of diffusion-weighted imaging and dramaticallyreduces the sensitivity of image quality to patient motion.UPMC uses both PROPELLER HD and FSE imaging techniques for T2-weighted imaging on essentially all brain MR examsperformed on the Signa 1.5T MR imaging system.

“When we were introduced to PROPELLER HD, motion reductionwas just one of several benefits mentioned,” Dr. Kanal said.“We expected improved signal-to-noise ratio, improved contrast-to-noise ratio and lower sensitivity to field distortion.We do indeed see all those, but by far for us the greatestbenefit lies in motion reduction. We have been truly amazedat the degree, reproducibility and reliability of motion reductionprovided by the PROPELLER HD sequence.

PROPELLER HD software has two types of motion reductionbuilt in,” Dr. Kanal observed. “It can detect and correct forrotation and translation in the same plane. For motion that is very severe, and especially motion through a plane, if the

Acquisition of a volunteer who did not move during the study. Volunteer who intermittently moved their head 90-degrees to the left, 90-degrees to the right, as far up as possible, and then as far down as possible. Note the absence of motion on the PROPELLER HD image.

PROPELLER HD and FSE acquisition of a volunteer who constantly movedtheir head 30-degrees from side to side throughout the study. Note theimage degradation from motion in the FSE image.

Volunteer who intermittently looked in three different directions during the scan. Note the lack of motion in the PROPELLER HD acquisition.

FSE acquisition PROPELLER HD acquisition FSE acquisition PROPELLER HD acquisition

FSE acquisition PROPELLER HD acquisition FSE acquisition PROPELLER HD acquisition

“Our worst-case motion (continuous coarse motion)still continued to provide diagnostic images on virtually every slice.”

Emanuel Kanal, M.D.

Emanuel Kanal, M.D.



As part of the study, motionless images with FSE and PROPELLER HD were also taken for study and comparison. Scan times were identical in all FSE and PROPELLER HD motionless and motion studies.

In each case, separate exams were conducted with PROPELLER HD and standard FSE and then evaluated via side-by-side direct visual comparisons. Scan time was rigidly controlled at two minutes and 42 seconds for eachsequence, PROPELLER HD T2 weighted imaging, as well asfast spin echo (FSE) T2 weighted MR imaging technique. “Inthe PROPELLER HD sequences, it was difficult if not impossibleon many images to even detect that any significant motion had occurred during data acquisition,” Dr. Kanal said. “Ourworst-case motion (continuous coarse motion) still continuedto provide diagnostic images on virtually every slice – I wouldreadily sign my name to a report describing the findingsof such an exam. In the formal study performed at my site using myself as the volunteer, every image obtained on every slice of each type of motion studied was of diagnostic image quality.

“On the FSE sequences, it was either evident or extremelyevident that motion had occurred. On the continuous coarsemotion study with FSE, it was difficult even to identify theanatomic region being studied.”

Comparisons between PROPELLER HD and FSE images from clinical cases show similar results. “In all cases of truepatient motion studied to date, the PROPELLER HD images are not just better, they are so noticeably and dramaticallybetter that I often end up calling my co-workers to showthem the comparisons,” Dr. Kanal said.

Dr. Kanal observed that due to the manner in which PROPELLERHD imaging is performed and the new imaging control parameters it introduces, radiologists are required to modifysome of their referred imaging parameters, which they



software detects that it cannot adequately correct it , thenthe motion-altered data is rejected entirely.”

Dr. Kanal conducted formal motion reduction studies atUPMC, using himself as the subject so that he could strictlycontrol and quantify the various types of motion being studied.During exams lasting two minutes and 42 seconds, he studiedsix different kinds of motion commonly encountered in clinicalsettings, which he labeled as follows:

• Sight-seeing: Intermittent patient motion that entails turning and rotating the head randomly in time and space through all three axes, much as a patient might inresponse to a noise, then returning the head to its originalposition. This was repeated numerous times during thedata acquisition.

• Twitch: Sudden violent head jerks repeated several timesthroughout the examination.

• Coughing: Spasms of five consecutive coughs, repeatedevery 10 to 15 seconds.

• Continuous coarse motion: Continually rocking the head30 degrees left, then 30 degree right, every one to twoseconds. This was continued without pause throughoutthe entire examination.

• Continuous fine motion: Simulating the fine tremor typemotion of a patient with Parkinson’s disease, fine continuoushead tremors continued without pause throughout theentire data acquisition.

• Maximum/90 degree rotations: A variation of sight-seeing,this motion consisted of intermittently rotating the headmaximally to the right, then to the left, followed by maximalneck extension and finally maximal neck flexion. This cyclewas repeated five times throughout the two minute and42 second scan acquisition time and was designed to testthe robustness of the motion reduction algorithm for bothin plane as well as through plane types of patient motion.

“I have no doubts that PROPELLER HD imagingwill succeed in winning over the entire globalMR imaging community.”

Emanuel Kanal, M.D.




had been accustomed to using to date. However, he noted,PROPELLER HD is easy to use once those adjustments aremade. “I truly cannot overstate the pleasant surprise weexperienced in the magnitude, reproducibility and robustnessof the motion reduction algorithm inherent in the PROPELLERHD software,” Dr. Kanal said. “Even with the improved signal-to-noise ratio and the sensitivity to image susceptibility artifacts, it was the tremendously successful and robustmotion reduction capabilities that proved to be the benefit of PROPELLER HD imaging that we found most noticeableand advantageous to us at the University of PittsburghMedical Center. This one is a real winner. I have no doubtsthat PROPELLER HD imaging will succeed in winning over the entire global MR imaging community, and will rapidlybecome a routine addition to the imaging armamentariumof all clinical and research MR sites.”

About UPMC Presbyterian

UPMC Presbyterian, located in the heart of Oakland, is an adult medical/surgical referral hospital and a site of ongoingresearch and graduate programs in conjunction with theUniversity of Pittsburgh School of Medicine. The hospital is arenowned center for organ transplantation, and a recognizedleader in cardiology and cardiothoracic surgery, critical caremedicine and trauma services, and neurosurgery. UPMCPresbyterian also is designated as a Level I Regional ResourceTrauma Center. Founded in 1893, UPMC Presbyterian continuesto provide state-of-the-art medical care to patients in the tri-state area and throughout the world. �





Harris Methodist Fort Worth (HMFW) Hospital is the flagship facility of HarrisMethodist Hospitals. For more than 70 years, the hospital has provided sophisticatedmedical services to the Tarrant County community, delivered with compassionand commitment. Radiology is an important tool that physicians on the medicalstaff utilize in diagnosing and developing many treatment options for their patients.

“We recently upgraded our GE Signa® 1.5T to the Signa HD system level, includingPROPELLER™ HD software,” said Kevin Spears, Outpatient Imaging and MRIServices Manager at Harris Methodist Fort Worth (HMFW) Hospital in Fort Worth,Texas. “Improvements in time and image quality were immediately noticed on scans utilizing the PROPELLER HD option.”

T2 FLAIR image showing typical results when apatient moves their head during the scan.

T2 FLAIR PROPELLER HD acquired on the samepatient. The images are routinely free of motionartifact and blurring, and demonstrate exquisitesoft tissue contrast and high signal-to-noise ratio.

Signa HD with PROPELLER HDProvides Efficiency and ImageQuality Enhancements

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“As far as the improvements in time go, PROPELLER HD makes the biggest differencefor the patients that tend to move around quite a bit during their exam,” Spearsexplained. “I would say we have seen a decrease of five to 10 minutes per casedue to the abilities of PROPELLER HD to acquire diagnostic T2 and FLAIR images,even with patient motion. I think the biggest impact it has had at HMFW is that we have not had to cancel exams on our ICU patients like we did before usingPROPELLER HD. Before PROPELLER HD, we were canceling or rescheduling 20 to 30 percent of our ICU patient’s MRIs. Since we incorporated PROPELLER HDinto our protocols, we have seen that number drop to near zero.

The improvements in image quality that PROPELLER HD provides result in better quality on our T2 and FLAIR sequences while allowing us to obtain two additionalexams a day that would have been cancelled or rescanned due to non-diagnosticsequences,” Spears added.

About PROPELLER HD

PROPELLER HD imaging uses a novel approach to measure spatial frequencies.After each excitation (each shot), PROPELLER HD measures spatial frequenciesalong a strip or blade, which goes through the central region of k-space. This isusually done by using all the echoes from a single central shot of a multishot fastspin echo (FSE) readout. For each subsequent shot, the blade is rotated until all thenecessary spatial frequencies that form a complete image are measured. Thedata from each blade (each TR) can be used to form an image, which contains allof the low frequency information inside of that circle plus limited high frequencyinformation.

The data from these blades can be combined in k-space to form a complete image.This resampling of the low spatial frequencies in every shot is a key element of PROPELLER HD. Since the image formed from these data should look identical, one can look for inconsistencies from shot to shot, and correct the data accordingly.

Reconstructions can be developed to correct for in-plane motion (translation androtation), phase inconsistencies (such as those introduced with diffusion lobes) and reject uncorrelated data (such as bulk through-plane motion). �

“We have not hadto cancel examson our ICUpatients like wedid before usingPROPELLER HD.”

Kevin Spears

Kevin Spears is the OutpatientImaging and MRI Services Managerfor Harris Methodist Hospital of Fort Worth. He oversees theday-to-day operations of theOutpatient Radiology department,which includes the modalities ofComputed Tomography (CT),Magnetic Resonance Imaging (MRI),Ultrasound (US) and DiagnosticRadiology. He holds certificationthrough the American Registry of Radiologic Technologist (ARRT)as a Radiographer as well asadvanced certifications inComputed Tomography andMagnetic Resonance Imaging.Kevin is also licensed as a CertifiedMedical Radiologic Technologist(CMRT) through the TexasDepartment of State Health Services.

Kevin Spears

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C L I N I C A L V A L U E B R E A S T I M A G I N G – V I B R A N T

Improving Breast DiagnosisUsing High-Resolution MRI

Introduction

The role of Magnetic Resonance Imaging (MRI) in breast diagnosis is evolving astechnology improves and clinical experience with new techniques expands. In the past four years, the number of breast MRI exams performed annually in the U.S.has more than quadrupled, as compared with a 23 percent increase in MRI exams

overall. This tremendous growth is due not only to more widespread acceptanceof breast MRI as a problem-solving tool outside the university hospital setting,

but also to the recognition that breast MRI may be clinically useful in othercontexts as well. Additionally, improvements of commercially available

breast MR imaging techniques is driving greater acceptance of thetechnique in busy clinical settings.

Mount Carmel Breast MRI Program

The Mount Carmel hospital system is composed of three mainhospitals in Columbus, Ohio as well as several outpatient imaging

centers. Breast MRI is performed using GE Signa® HD 1.5T scanners(GE Healthcare; Waukesha, WI) at four locations. Image data is

transmitted to one of two reading stations, both equipped with computeraided detection (CAD) computers. The interpretations are provided by one of threededicated radiologists who are part of a 47-member private practice radiologygroup. All three have fellowship training in MRI and are also actively reading mammograms as part of our general practice. Each radiologist began by attendinga dedicated breast MRI program to learn the pathophysiology and basic interpretiveskills of breast MRI. The number of radiologists interpreting breast MRI has beenlimited by design to maintain an adequate number of cases per reader to assureinterpretive expertise. Since introducing breast MRI into our practice four-and-a-halfyears ago, we have seen our breast MRI caseload grow from two to three casesper month to our current rate of four to eight cases per day. We have imagedapproximately 2,000 patients to date.

MR Breast Imaging Using VIBRANT

At Mount Carmel hospitals, all breast MRI exams are performed on GE Signa 1.5Tscanners with a variety of software platforms and gradient performance. We usea variety of coils including 4-channel, 7-channel and 8-channel phased array

By Dr. Daniel J. White, M.D.Director, Magnetic Resonance Mammography Mount Carmel Hospital SystemMedical Director, Mount Carmel Imaging CenterSenior Partner, Radiology Inc.

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breast coils. Due to differences in scanner capabilities at ourfour breast MRI facilities, we utilize a range of techniques frombasic 2D T1-weighted gradient echo imaging relying on sub-traction techniques to assess enhancement, to more sophis-ticated 3D axial and sagittal fat saturated imaging usingVIBRANT™ (See Table I for detailed protocol descriptions).

VIBRANT is a specialized breast imaging pulse sequencerecently developed by GE. The sequence is based on a fast 3D gradient echo sequence with T1-weighting and fatsuppression, and has special modifications to optimize theimage quality for breast imaging. With VIBRANT, parallelimaging may be applied to an axial or a sagittal volume. If asagittal volume is defined, the parallel imaging accelerationis applied along the slice axis of the volume, i.e. in the L/Rdirection, to obtain true sagittal images without prolonging

scan time. Regardless of which orientation is used to acquirethe images, reformatted images may be obtained from theacquired volume in any orientation, but with the proviso that the spatial resolution is significantly lower along theslice direction.

1) Standard 2D T1 Gradient• 3 plane loc, slice 7mm/gap 5mm

• Axial 2D, T1 gradient, slice 4.0/0.0, matrix 256 x 160, FOV~34.One pre-contrast and 5 post sequences are run in one series.

• Coronal FSE T1 (no fat sat ), slice 2.0/0.0 (may need to increase to 4.0 depending on pt size)

• Axial 3D fat sat SPGR, slice 2.0/0.0, matrix 256 x256, FOV~34

• Axial STIR, slice 4.0/0.0, matrix 224x224, FOV~34

• Axial FSE T2 (no fat sat), slice 2.0/0.0, 224 x 224, 34

2) Sagittal VIBRANT• 3 plane loc, 7.0/5.0

• Axial calibration scan, slice 8.0/0.0, FOV 48

• Sagittal VIBRANT, slice 4.0/0.0 (ZIP2 to effective 2.0 mm slicethickness), matrix 224 x224 (ZIP 512). One pre-contrast and five post-contrast acquisitions simultaneously of both breasts.

• Axial VIBRANT, slice 2.6/0.0, matrix 350 x350, FOV~38-40.One delayed post-contrast acquisition.

• Axial FSE T1 (no fat sat), slice 2.0/0.0, matrix 224 x 224, FOV~34

• Sagittal FSE T2 (no fat sat) Left breast, slice 2.0/0.0, 224 x 224,FOV=24

• Sagittal FSE T2 (no fat sat) Right breast, slice 2.0/0.0, 224 x 224,FOV =24

• Axial STIR, slice 4.0/0.0, 256 x 192, FOV~38

3) Axial VIBRANT• 3 plane loc

• Cal scan

• Axial VIBRANT, slice 2.6/0.0 (ZIP 2 to effective 1.3mm), 350 x 350(ZIP 512), FOV~40. One pre-contrast and five post-contrastacquisitions.

• Sagittal VIBRANT, slice 4.0/0.0 (ZIP 2), 224 x 224, FOV~24

• Axial T2 FSE (no fat sat), slice 2.0/0.0, 224 x 224, FOV~34

• Coronal FSE T1 (no fat sat ) , slice 2.0/0.0 (may need to increase to 4.0 depending on patient size)

• Axial STIR, slice 4.0/0.0, 256 x 192, FOV~34

Table I. Mount Carmel East Imaging Center – Breast MRI Protocols

Case 163-year old female with left breast pain, heterogeneously dense breast tissueand a strong family history of breast cancer. Earlier mammograms revealeda focal asymmetric density in the superior region of the left breast, consideredto have a benign appearance, and calcifications in the anterior superiorregion of the right breast. MR exam showed no abnormal enhancement inthe left breast but revealed a 9 x 7 mm nodule of abnormal early contrastenhancement in the immediate subareolar right breast, demonstrating pronounced early enhancement with washout kinetics.

Subsequent biopsy revealed invasive carcinoma with adjacent low-gradeductal carcinoma (cribriform type). Histologic analysis of the mastectomyspecimen showed a 0.7 x 0.6 cm area of residual carcinoma adjacent to the 2.5 cm biopsy cavity.

One minute subtraction MIP images

Right breast, one minute fat saturated image with color parametricenhancement map (on left) and enhancement curve.

Right and left MLO view mammograms





Case 240-year-old woman presented with a palpable lump in her left breast.Mammography revealed dense breast tissue throughout the breasts and an irregularly-shaped asymmetric neo-density in the left breast at the site of the palpable lump. Asymmetric tissue was also noted in the axilliary tail of the left breast, unchanged from prior management. Ultrasound confirmeda 14 x 12 x 9 mm irregularly shaped hypoechoic solid-appearing mass showingposterior acoustic shadowing at the location of the palpable lump. A biopsyrevealed infiltrating ductal carcinoma in a background of DCIS. MRI demonstrateda dramatic asymmetric enhancement, involving the entire upper outer quadrant of the left breast. Histologic analysis of the left mastectomyspecimen demonstrated multi-focal, multi-centric infiltrating ductal carcinoma with the largest tumor nodule measuring 1.4 cm correspondingwith the palpable mass. Intervening DCIS filled the upper outer quadrant.

Right and left MLO view mammograms

One minute subtraction MIP images

A one minute fat saturated image of the left breast; same image with a colorparametric map of the enhancement.

All imaging protocols, regardless of scanner performance,were designed to provide simultaneous, dynamic imaging of the breasts bilaterally (< 80 seconds per acquisition, optimally 60 to 70 sec.). Except in the case of prior mastectomy, we feel it is critical to image both breastssimultaneously for all studies.

Image Analysis Using a CAD System

We have found the use of a computerized automated detectionsystem to be an essential component of our breast MRI program. We began our program without a computer-aideddetection (CAD) system, evaluating enhancement kinetics by manually placing regions of interest and attempting to correlate multiple pulse sequences. This was slow, laborintensive and often less accurate. Any minor error in theregion of interest positioning can significantly change anenhancement kinetic curve. We would never go back to that method. Our CAD system, CADstream™ (Confirma, Inc;Kirkland, WA), has improved our interpretation speed byorganizing and correlating the 1,200 to 1,500 images that we produce with each study. We believe that CAD alsoimproves our accuracy through voxel-by-voxel evaluation of enhancement kinetics, motion correction algorithms andgeneration of color parametric overlays. Although we feel an exam should never be “read by color,” the color mappingserves to draw your eye to regions or lesions requiring further evaluation.

Conclusions

Breast MRI is an essential component of the comprehensivebreast care program at our facilities. Over the past four-and-a-half years since we introduced breast MRI into our practice,the number of exams per year has increased and continuesto increase dramatically. When performed correctly, in thecontext of a dedicated breast MRI program, this imagingmodality frequently results in improved patient care. As morephysicians experience this first-hand with their own patients,they begin to incorporate this exam more often into theirpatient care algorithms We consider breast MRI a criticalcomponent in our approach to breast imaging, and use it routinely for a variety of problem-solving scenarios togreatly increase the clinician’s or surgeon’s confidence. Theresults are excellent, often providing critical information fordetermining the appropriate course of patient care. We feelthat breast MRI technology has attained a degree of maturitythat allows it to be effectively incorporated into a busybreast imaging practice. �



GE Healthcare

How do you capture difficult images?

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GE Healthcare

Applications that make it easy. You’ve never scanned with such ease or confidence. LAVA-XV lets you scanyour patient’s entire abdomen with one injection. One scan. One breath-hold.

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MR Echo produces high-definition cardiac images in even the sickest patientswithout breath-holding or ECG gating. VIBRANT lets you examine both breastsat the same time without compromising resolution or scan time. And TRICKSgives you a whole new level of accuracy in timing for vascular imaging withfour times the acceleration of traditional MR angiography.

Start by capturing the imagination.There have always been patients who have been difficult to image. But through the eyes of GE’sSigna® High Definition MR, you get a new view ofyour patients. Clearer and more accurate. So youcan diagnose quickly and with more certainty.

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More innovative. More friendly.The speed of our Signa HD machines makesit easy to scan more patients every day. Theuser interface is so simple and intuitive it iseasy to quickly become a power user.Whether a technologist is using a 1.5Tscanner or a 3.0T, scanning is just a clickaway. Our detachable dual tables are an

innovation in patient care. Prep one patient while you scan another. Quicklymove a patient in the event of an emergency. And easily integrate upgradeslike focused ultrasound ablation technology.



GE Healthcare

© 2006 General Electric Company GE Medical Systems, a General Electric Company doing business as GE Healthcare

An MR for every facility and every body. 3.0T – Signa HDx 3.0T, Signa HD 3.0TSigna is the 3.0T leader, withthe most 3.0T systemsinstalled worldwide. Capturedetail you couldn’t seebefore. High-performancehigh-definition imaging capabilities helpyou diagnose your most challenging cases.

1.5T – Signa HDx 1.5T, Signa HD 1.5T,Signa HDe 1.5TPowerful, high-definition MR delivers a moredefinitive image and a full complement ofapplications. Choose the highest perform-ance Signa HDx, the 16 channel Signa HDor the smaller and simpler Signa HDe thattakes up 30% less space.

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Capturing images you could once onlycapture in your imagination. MR Re-imagined.





For the women of Florida, Magnetic Resonance (MR) is proving itself a highly effective method for imaging the breast.

At least this is the assessment of Susan Curry, M.D., founder and medical director of the Women’s Center for Radiology in Orlando.Having opened its doors in 1981 as one of the nation’s first outpatientpractices dedicated exclusively to women’s health, the Center todayconducts more than 90,000 procedures annually from two offices –one dedicated to screening, the other to diagnostics.

The Center’s two offices, four Board-certified radiologists and 44-personsupport staff currently welcome about 200 women each day for the fullrange of breast screening and diagnostic procedures, Dr. Curry said –including digital mammography, whole-breast ultrasound and minimally invasive image-guided biopsy. In addition, ob/gyn sonographyand bone-mineral densitometry are routinely provided.

Since the October, 2004, acquisition of a GE Signa® 1.5T MR systemwith VIBRANT™ signature application for breast diagnostics – a systemthat has since been augmented with the Signa HD upgrade – theCenter’s procedural load has expanded to include leading-edge breast MR.

Outstanding Clinical Performance

“MR offers consistently superior visualization of the breast,” Dr. Currysaid. However, Dr. Curry stops short of recommending breast MR alonefor high-risk patients.

“It has not yet been shown to replace mammography. Microcalcificationsthat we see on mammography may not show up on MR.”

“With what we know today, it’s best to use both tests for these patients.”

As a result, mammography and breast MRI are now routinely prescribedfor the Center’s high-risk patients – those with a family or personalhistory of breast cancer, for example, as well as those proven to behigh-risk by prior biopsy.

Breast MR ProvidesPioneering Clinic withExcellent ROI WhileEnhancing Patient Care

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Partly as a result of these capabilities, the Signa HD 1.5T systemis delivering an excellent return on investment, Dr. Curry said.

“We knew up front that we needed to do two to four patientsa day to break even. And I was frankly worried about that. Asit turns out, my fears were unfounded; we are now averagingten to twelve patients a day.

“So it’s a good investment, just as digital mammography hasbeen for us. In both cases, we get better studies and higherreimbursements. And with more accurate results and fewerrecalls, our patients are better off, too.”

On the Horizon

Dr. Curry expects the Center’s volume of 2,500 MR proceduresa year to continue growing as more physicians and womenunderstand the significant advantages MR brings to the table.

The Center is now applying MR technology to another areaof critical importance to women: cardiac MR, an ideal diagnostictool in an era where women’s unique cardiology needs aremaking headlines everywhere.

Dr. Curry’s husband is a cardiologist who believes that MR is an excellent test for symptomatic women, as well as forfollowing the hearts of those who are on certain types of chemotherapy.

While reimbursement remains an issue for this application,she believes that will eventually change.

Breast cancer may be more of a threat to younger women,she pointed out, but heart disease remains the number one killer of women.

“We have in MR a non-invasive and highly-accurate test, and I believe it will one day become the dominant test for cardiac diagnostics.”

As committed as they are to women’s health, Dr. Curryadded, she and her colleagues are proud to be pioneeringMR’s application in fighting both of these deadly diseases. �

Case in Point

Dr. Curry believes that breast MR is already saving lives. “Notlong ago, a surgeon came to us with a palpable mass thatwasn’t showing up on mammography or ultrasound. Youcan’t do a random needle biopsy, of course, so she asked us for a breast MR. We were able to see the lesion clearlyand biopsy it on the spot.”

Dr. Curry said that, in some cases, multiple lesions will showup on mammogram and ultrasound, raising the prospect of multiple biopsies for the patient. “With MR, we can some-times eliminate the need for this sort of trauma.”

A Financially Sound Decision

Reimbursement is, quite naturally, a factor that can determinethe viability of an equipment investment. Fortunately, Dr. Currysaid, diagnostic breast MR is now reimbursed nationally, andher office manager is working with insurers to encouragecoverage of screening MR for high-risk women.

To ensure a sound financial decision for her practice, Dr. Curryand her colleagues evaluated a range of MR scanners beforeselecting GE Healthcare’s Signa HD 1.5T system.

“We were taking a considerable risk with this investment,”she said. “We decided that if we were going to do it , we were going to do it right, with state-of-the-art equipment –an 8-channel MR coil, power injector, CAD, the works. We’reconvinced we made the right choice across the board.”

The Signa HD 1.5T system not only provides the Center withoutstanding resolution and thin-slice capabilities, it also offersa number of unique capabilities – with sagittal acquisitionbeing a prominent example.

“Being a mammographer, sagittal views make it much easierfor me to read the exam.”

This system also makes short work of even complex procedures, she added.

“It accommodates bilateral imaging so that we can completethe entire exam in less than a half hour. ”

When used with CADstream (Confirma Inc., Kirkland, WA), the system streamlines MR-guided biopsies performed at the center.

“The GE Signa 1.5T MR system with VIBRANT accommodatesbilateral imaging so that we can complete the entire breastMR exam in less than a half hour.”

Susan Curry, M.D.





Susan Curry, M.D.

Case 2Patient is a 39-year old with family history of breast cancer. Screening mammogram with no symptoms. Patient is currently breast feeding with a nine-month old infant. Normal mammogram with dense tissue. No masses ormicrocalifications noted. MRI reveals a 2 cm x 1.4 cm x 1.0 cm irregular mass with abnormal kinetics of rapidwash in and rapid wash out. Sonogram confirmation shows solid lobular mass, non-palpable that with sono core biopsy reveals invasive ductal carcinoma.

Case 1Patient is a 48-year old pre-menopausal woman with dense tissue and a family history of breast cancer (hermother at age 52) with prior stereo core biopsy three years ago for microcalcifications that we biopsied provenfibrocystic. A normal mammogram with dense tissue, normal sonogram with few cysts all less than 1 cm. Hadbreast MR that reveals a rim enhancing mass at 12:00 of the left breast measuring 1 cm with abnormal kinetics of rapid wash in and rapid wash out. The right breast reveals a lobular mass, upper outer quadrant with rapid washin and plateau kinetics. MRI Biopsy, left invasive ductal carcinoma, the 2nd area was felt by surgeon to be a cyst. A follow-up MRI showed same area of the right breast which by MRI biopsy was also an invasive ductal carcinoma.

Susan Curry, M.D., founder andmedical director, is a diplomate ofthe American College of Radiologyand is Board Certified in DiagnosticRadiology and Nuclear Radiology.She completed her training at theUniversity of Florida, College ofMedicine and is fellowship trained.She was Instructor in Radiologyand Assistant Professor ofRadiology. She was Chief ofNuclear Medicine services at theUniversity of Florida. Dr. Curry is a member of Phi Beta Kappa,Mensa and a member of manyorganizations and societies includingthe AMA, the American College ofRadiology and the Society of BreastImaging. Dr. Curry has been activelyinvolved in several clinical trials andhas been reading mammogramssince 1978 and performing stereo-taxic biopsies since 1992.

In October 2004, the Women’sCenter for Radiology completed the installation of its GE HealthcareSigna EXCITE Echo-Speed, HighField (1.5 Tesla) MRI system.Women’s Center for Radiology wasfirst facility in Florida to offer theVIBRANT (Volume Imaging BReastAssessmeNT) protocol, and in 2005was the first again to upgrade to the Signa HD MR system.




C L I N I C A L V A L U E N E U R O – D I F F U S I O N T E N S O R I M A G I N G / F I B E R T R A K

Tensor imaging and tractography are diffusion-based MR techniques for advancedfunctional imaging of brain white matter.1 Imaging brain anisotropy can yield usefulinformation about white matter (WM) integrity and demonstrate pathology occult toconventional imaging techniques. Anisotropy imaging can also provide informationabout ordered white matter tracts such as directional orientation and connectivity,which can be useful in the understanding of certain developmental and acquireddisease states.

With appropriately applied magnetic field gradients, MR images can be sensitized to diffusion, or the random thermally driven motion of water molecules in tissue.Water movement is essentially random in brain gray matter, but diffusion isanisotropic, or directionally oriented, in WM tracts. There, axonal membranes andmyelin sheaths present barriers to water motion in directions other than parallel to fiber orientation. The direction of maximum diffusivity coincides with WM fibertract orientation.

This information is contained in the diffusion tensor, a mathematical model of diffusion in 3D space. The tensor is a matrix of numbers derived from diffusionmeasurements in at least six different directions from which diffusivity in anydirection can be estimated and the direction of maximum diffusivity can be determined.

The tensor matrix can be visualized as an ellipsoid. The diameter in any directionestimates the diffusivity in that direction, and the major principal axis is oriented in the direction of maximum diffusivity. The degree to which the diffusion tensorshape differs from that of a sphere (random motion) represents anisotropy(ordered motion).

With diffusion tensor imaging (DTI), the degree of anisotropy as well as local fiberorientation can be mapped, providing an opportunity to study WM architectureand evaluate fiber integrity.

WM fiber tracts are classified as association, projection, or commissural fibers(Table 1). Association fibers connect cortical areas in each hemisphere. Projectionfibers connect cortical areas with deep nuclei, brain stem, cerebellum, and spinal cord. Commissural fibers connect similar cortical areas between opposite hemispheres. Three-D tract rendering is accomplished with commercially available

Diffusion Tensor Imaging DeliversCrucial InformationUse in Clinical Practice to Work Up All Lesions Considered for SurgicalResection can Reduce Impact on Eloquent Structures

By Lawrence N. Tanenbaum, M.D., FACR

Association Fibers• Cingulum

• Superior occipitofrontal fasciculus

• Inferior occipitofrontal fasciculus

• Uncinate fasciculus

• Superior longitudinal (arcuate) fasciculus

• Inferior longitudinal (occipitotemporal)fasciculus

Projection Fibers• Corticospinal tracts

• Coricobulbar tracts

• Corticopontine tracts

• Geniculocalcarine tracts (optic radiations)

Commissural Fibers• Corpus callosum

• Anterior commissure

Table 1. Fiber Types and Locations

Figure 1. 3D tractogram

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C L I N I C A L V A L U EN E U R O – D I F F U S I O N T E N S O R I M A G I N G / F I B E R T R A K

software that can be found on the scanner or workstation.While individual tract parsing is imperfect, in some circumstances incompletely extracting individual tracts,these techniques are still quite efficacious at display andevaluation of the ordered WM.

Clinical Utility

DTI has also been used to investigate brain development and assist in understanding the organization of the brainwhite matter in developmental brain abnormalities, oftendemonstrating additional findings beyond those seen with conventional MR imaging (Figure 1).2

The preservation of vital cerebral function while maximizinglesion resection is the principal goal in brain neurosurgery.Cortical mapping can be accomplished intraoperatively withelectrocortical stimulation. Preoperatively, functional MRtechniques such as blood oxygen level-dependent (BOLD)imaging are used in the localization of eloquent cerebral cortex. Neither cortical mapping nor BOLD imaging providesinformation about WM tracts in or adjacent to brain lesions,however. Two-D and 3D WM tractography techniques can

Figure 2. Case study 1. 2D and 3D tractography reveal lateral displacement of the posterior limb of the internalcapsule (coded blue).

Figure 3. Case study 1. 2D and 3D tractography reveal inferior and lateraldisplacement of the posterior limb of the internal capsule, encouragingresection from a medial approach.

Corticospinal fibers

Corticospinal fibers

Posterior limb internal capsulePosterior limb internal capsule

Posterior limb internal capsule

Anterior limb internal capsule

Posterior limb internal capsule

External capsule and postlimb internal capsule

be very powerful in elucidating relationships of deep brainlesions to eloquent brain structures.3

White matter imaging is used to estimate the relationship of the lesion to tracts responsible for brain activity such as motor function (corticospinal tracts). DT tractography,which requires five to seven minutes to scan and is easilyprocessed with commercially available software, is practicaland easily integrated into the armamentarium of techniquesof the high-end neurologically oriented clinical practice, as shown in the following examples.

Case study one. A 13-year-old girl, diagnosed at an outsideinstitution with a low-grade thalamic glioma, was referred to the New Jersey Neuroscience Institute for evaluation forresection. As a critical part of the planning process, surgeonsrequested a 3T MR study for detailed anatomic delineation andfunctional localization. Imaging revealed a well-circumscribed,nonenhancing left thalamic mass distorting local anatomyand obscuring relationships with the adjacent internal capsule.Definitive localization of the blue corticospinal fibers coursingin a cephalocaudal direction was made possible by thedirectionally encoded 2D tensor images (Figures 2 and 3).

These images, along with 3D tractograms seeded and grownfrom the ipsilateral precentral gyrus WM, showed that thelesion displaced the posterior limb of the internal capsule laterally and inferiorly. The anterior limb of the internal capsule,coded in green as its fibers course anteroposteriorly, wasdisplaced anteromedially. Armed with this functional information, the surgeon resected from a medial approach.After several days, the patient was discharged with no motor deficit after resection.




C L I N I C A L V A L U E N E U R O – D I F F U S I O N T E N S O R I M A G I N G / F I B E R T R A K

Case study two. A 35-year-old woman with seizures presented with an outside institution MR study showing a left temporal lobe hemorrhage and other findings suspiciousfor the presence of an arteriovenous malformation. Thepatient was referred to Edison Imaging for definitive 3T MRevaluation of the presence of an AVM as well as estimationof the functional significance of lesion resection. Time-resolved contrast-enhanced MRA confirmed the presence of an AVM within the left temporal lobe. Functional MR withBOLD imaging clearly defined the central sulcus and sensori-motor cortex on the surface of the brain but yielded littleinformation related to the surgical approach to the temporallobe lesion (Figures 4 and 5).

Three-D tractography demonstrated that the lesion andhematoma were separate from the superior longitudinal fasciculus. The optic radiations and inferior longitudinal fasciculi had been destroyed by the lesion, and thus functionwas not likely to deteriorate further as a result of surgicaltreatment of the AVM.

Case study three. A 60-year-old patient with a solitarymetastatic focus was referred for consideration of resection.Routine anatomic imaging at 3T showed a hypointensemetastasis in the vicinity of eloquent cortex. Three-D tractograms obtained by seeding the pre- and postcentralgyri, as determined by BOLD imaging, confirmed the lesionwas posterior to the sensory cortex, allowing lesion resectionwithout deficit (Figure 6).

Case study four. A 40-year-old patient with a recurrent high-grade glioma was referred for consideration of lesiondebulking. BOLD imaging readily marked the central sulcus,showing that the enhancing portion of the lesion was wellposterior to eloquent cortex. Localization of WM fibers withrespect to the deeper portions of this large neoplasm wasfacilitated by 3D tractography. The corticospinal fibers wereclearly displaced and bowed anteriorly by the tumor. Lesiondebulking did not produce a motor deficit (Figure 7).

Figure 4. Case study 2. Left temporal hemorrhage and flow voids suggestan arteriovenous malformation (left). MRA confirms the presence of a vascular lesion (right).

Figure 5. Case study 2. BOLD study (upper left) identifies central sulcus. 3D tractography (upper right) reveals hemorrhage to be inferior to superior longitudinal fasciculus. Axial T1-weighted image (lower right) and 3D tractogram (lower left) show destruction of portions of the optic radiations and inferior longitudinal fasciculus.

Figure 6. Case study 3. 3D tractograms reveal the hypointense metastaticfocus is posterior to sensorimotor white matter tracts.

Figure 7. Case study 4. BOLD study (upper left) suggest tumor infiltration ofsensory cortex. Enhancing portion of lesion is inferior and posterior to post-central gyrus (bottom). 3D tractogram (upper right) shows corticospinal tractsdisplaced anteriorly.



Lawrence N. Tanenbaum, M.D.

Dr. Tanenbaum is section chief for MR,CT, and neuroradiology at EdisonImaging-JFK Medical Center, NewJersey Neuroscience Institute, SetonHall School of Graduate MedicalEducation.

The systems used by Dr. Tanenbaumfor the clinical applications describedin this article are GE Healthcare’sSigna® MR HDx 1.5T and 3.0T scanners.

Dr. Tanenbaum and his associateshave used GE MR scanners since1989. “They have consistently deliveredstate-of-the-art imaging techniquesthat have assisted me in my clinicalpractice and provide the highestquality image and most refined diagnosis. With each new generation,there are new capabilities andimproved efficiency,” Dr. Tanenbaumsaid. “In general, images haveextraordinary quality and consistency.”

He noted ease-of-use and scannerefficiency are additional benefitsderived from his use of GE’s MRscanners. This is particular importantwhen performing advanced neuroimaging techniques usingadvanced applications like FiberTrak.

“With diffusion tensor imaging andFiberTrak, we can take a five to sixminute imaging acquisition and create2D and 3D images of the white mattertracks within the brain in an efficientand user-friendly fashion. Much ofour routine imaging requirementscan be accomplished by the technologist at the operator’s console.

FiberTrak has made a significantcontribution to our imaging practiceand is considered essential by myneurosurgical colleagues.”


C L I N I C A L V A L U EN E U R O – D I F F U S I O N T E N S O R I M A G I N G / F I B E R T R A K

Figure 8. Case study 5. 3D trac-tograms show temporal lesion ismedial to white matter tracts.

Figure 9. Case study 5. Lesion is posterior and medial to combined fibers ofoptic radiations, inferior longitudinal fasciculus, and inferior occipitofrontalfasciculus (lower left).

Inferior occipitofrontal fasciculus Inferior

longitudinal fasciculus

Optic radiations

Case study five. A 42-year-old man presented with seizures,and 3T MR imaging revealed a cavernous malformationwithin the occipital lobe. The goal of neurosurgery was toresect the lesion with minimal disruption of visual function.Tractography demonstrated that the lesion was lateral tothe optic radiations and largely inferior and posterior to theinferior longitudinal and inferior occipitofrontal fasciculi,leading to an inferiorly angled superior and posteriorapproach to lesion removal (Figures 8 and 9).

Clinical Impact

Advanced imaging tools using diffusion tensor imaging andtractography are poised to make a significant impact in theclinical imaging of patients with neurological disease. Yieldingstructural and functional information about ordered whitematter pathways in the brain, acquired and processed in a practical and efficient manner, is applicable in any settinginvolving the high-level practice of neuroimaging. �

References

1, Jellison BJ, Field AS, Medow J et. al. Diffusion tensor imaging of cerebral white matter: a pictorialreview of physics, fiber tract anatomy, and tumor imaging patterns. AJNR 2004;25:356-369.

2. Lee SK, Kim DI, Kim J et. al. Diffusion-tensor MR imaging and fiber tractography: A new method ofdescribing aberrant fiber connections in developmental CNS anomalies. Radiographics 2005;25:53-68.

3. Witwer BP, Moftakhar R, Hasan KM, et. al. Diffusion tensor imaging of white matter tracts inpatients with cerebral neoplasm. J Neurosurg. 2002;97(3):568-575.

Copyright© 2006 by CMP Media LLC, 600 Harrison Street, San Francisco, CA 94197 USA. Reprintedfrom Diagnostic Imaging with permission. Please note portions of this article have been modifiedfrom Diagnostic Imaging with permission from the author and Diagnostic Imaging.




C L I N I C A L V A L U E C A R D I O L O G Y – M R E C H O

The following case study illustrates how ourusage of real-time imaging with GE Healthcare’scardiac MR application MR Echo™ (Signa® HD1.5T) detected a physiologic abnormality thatwas not evident with standard breath-hold MR imaging.

Clinical Case

A 59-year-old man with a history of a myocardialinfarction developed chest pain during a businesstrip. EKG and echocardiography suggestedpericarditis. The patient improved followingtreatment with steroids. However, not longthereafter, the patient developed increasingshortness of breath and ankle edema whichrequired treatment with diuretics. After a fewmonths of worsening symptoms, cardiac MRIwas requested for further evaluation. Standardbreath-hold imaging (Figures 1 and 2) shows a small inferior myocardial infarction andabnormally thick pericardium, compatible with the patient’s known history of coronaryartery disease and pericarditis.

Real-time imaging with MR Echo (Figures 3 and4) demonstrates the key physiologic abnormality.Images show paradoxical septal wall motiononly during inspiration (arrow). This finding is indicative of the ventricular coupling thatoccurs with pericardial constriction. It cannotbe seen during conventional breath-held MRI.

A New Imaging Approach in CardiacMRI Reveals Physiologic AbnormalityBy Steven D. Wolff, M.D., Ph.D Director of Cardiovascular MRI, Advanced Cardiovascular Imaging Director of Cardiovascular MRI & CT, Cardiovascular Research Foundation New York, New York

Figure 2 Standard imaging shows thick pericardium

Figure 4 Real-time MR Echo shows paradoxicalseptal wall motion on inspiration

Figure 3 Real-time MR Echo on expiration

Figure 1 Standard imaging shows inferior infarct

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C L I N I C A L V A L U EC A R D I O L O G Y – M R E C H O

Steven. D. Wolff, M.D.

Steven. D. Wolff, M.D., Ph.D., is theDirector of Cardiovascular MRI at the Cardiovascular ResearchFoundation in New York. He is also the Director of CardiovascularMRI at Advanced CardiovascularImaging, a private practice inManhattan. His research interestsfocus on developing new MRI techniques that will have immediateapplications to clinical practice.

He is the inventor of severalpatents in MRI including the originalpatent on magnetization transfer.Dr. Wolff attended Duke UniversityMedical School for his medical anddoctoral studies. His doctoral workwas based on research he performedas a Howard Hughes MedicalInstitute – National Institutes ofHealth (NIH) Research Scholar. Dr Wolff completed his radiologyresidency at Johns HopkinsHospital in 1994.

About CRFThe Cardiovascular ResearchFoundation (CRF) is a global leaderin bringing together three elementsthat define modern medicine:research, education and patientcare. Founded in 1991, CRF hasplayed a key role in the developmentof nonsurgical and drug-basedtreatments of heart and vascular disease.

CRF’s MRI program, directed bySteven D. Wolff, M.D., Ph.D., wasestablished in May 2000 to performresearch and education in cardio-vascular MRI. Research and education are closely aligned with the Clinical CardiovascularMRI program at AdvancedCardiovascular Imaging.

Once the exam was complete, GE’sReportCARD™ reporting system distilled theentire cardiac MRI exam to a single, easy to understand page (Figure 5) that includesmeasurements, polar plots, and images –concisely communicating the diagnosis tothe referring physician – clearly showing the advantages of the cardiac MRI for comprehensive high-quality cardiac studies.

MR Echo

Presently, patients have to manage multiplebreath-holds to allow ‘whole heart coverage’for wall-motion and other studies. MR Echoeliminates the need for breath-holds byemploying a bright-blood, ultra-fast FIESTAsequence to freeze motion and significantlyreduce typical cardiac-exam times. Theintuitive MR Echo interface enables theoperator to quickly scan the heart in anyorientation and to save real-time images tothe browser through bookmarks. MR Echo’s

Scan & Save mode enables high-resolutionheart imaging with Vector Cardiac Gating(VCG); it also allows the prescription of multiplefunctional images over many slices, withscanning being completed in a singlebreath-hold. Because the system immediatelyposts the scan time required for the numberof slices prescribed, the operator is able totailor the scan to the patient’s breath-holdcapability. To ensure uninterrupted work-flow, all images acquired in Scan & Savemode are stored in the browser while the operator continues scanning.

Conclusion

MR Echo provided the capability to detectan abnormality in this patient’s physiologythat could not be seen with conventionalMRI, and the ReportCARD reporting systemprovided a complete and concise report for the referring physician. �

Figure 5 ReportCARD referringphysician report

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C L I N I C A L V A L U E C A R D I O L O G Y – R E P O R T C A R D

Abstract

The current ‘gold standard’ for detecting a patent foramen ovale(PFO) is the use of transesophageal echocardiography (TEE).This technique involves the introduction of the ultrasoundprobe into the esophagus while the patient is under sedation,suppressing the patient’s ability to valsalva during the test. Thereleasing of the valsalva manoeuvre raises the pressure in theright atrium, which enhances the bubble contrast as it passesthrough the PFO, confirming diagnosis on the ultrasound.

GE Healthcare introduced a new real time imaging protocolon Signa HD that suppresses signal from all tissues duringthe scan. The patient does not require sedation and is therefore

cooperative for the valsalva at the time of Gadolinium passage through the heart. The real-time suppressionsequence provides excellent contrast-to-noise ratio for visualizing the contrast agent as it crosses through the PFO fromthe right to left atrium. Along with the sequence, GE Healthcarealso introduced a tool in ReportCARD™ to graph the contrastchanges over time for incorporation into the patient’s report.

This new MRI technique is less invasive and more comfortablefor the patient and is an easier procedure for the technicianand clinician than TEE.

MR Evaluation of PatentForamen Ovale (PFO)By Stuart Clarkson, MR Cardiovascular Applications Product Manager, GE Healthcare

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C L I N I C A L V A L U EC A R D I O L O G Y – R E P O R T C A R D

Patent foramen ovale (PFO) is a flaplike opening between the atrial septa primum and secundum at the location of thefossa ovalis that persists after the age of one year. In utero,the foramen ovale serves as a physiologic conduit for right-to-left shunting. After birth, once the pulmonary circulation isestablished, left atrial pressure increases and allows functionalclosure of the foramen ovale. This is followed by anatomicalclosure of the septum primum and septum secundum by theage of one year. Autopsy studies show 27 percent prevalenceof probe-patent foramen ovale.

Contrast echocardiography is usually required to detect smallPFO. After obtaining optimal visualization of the atrial septumon transthoracic or TEE, a bolus of agitated saline is injectedinto an antecubital vein. Subsequently, microbubbles appearin the right atrium. The study is positive for patent foramenovale if the microbubbles appear in the left atrium withinthree cardiac cycles of their appearance in the right atrium.Valsalva maneuver increases right atrial pressure and facilitatesright-to-left shunting.

Transesophageal contrast echocardiography provides superior visualization of the atrial septum and therefore ispreferred to transthoracic echocardiography. However, TEE is an invasive and uncomfortable test for the patient.

Signa® HD provides the ability to assess PFO’s with a newimaging sequence. This suppresses signal from all tissuesallowing visualization of the intravenously-administeredGadolinium-base contrast agent.

The volume of blood shunted between the right and left atria is in the range of 0.4 to 0.6 mL per heart beat.

A PFO Analysis tool has been implemented to enhancedetection capabilities of the imaging sequence.

Summary

In assessment of patients under 55 years of age who sufferstroke, there is a potential patient benefit of undergoing MR evaluation for a PFO rather than transesophagealechocardiography, such as speed of exam and increasedpatient tolerance. �

References:

• Bogousslavsky J, Garazi S, Jeanrenaud X, et al: Stroke recurrence in patients with patent foramenovale: the Lausanne Study. Lausanne Stroke with Paradoxal Embolism Study Group. Neurology1996 May; 46(5): 1301-5.

• Bridges ND, Hellenbrand W, Latson L, et al: Transcatheter closure of patent foramen ovale afterpresumed paradoxical embolism. Circulation 1992 Dec; 86(6): 1902-8.

• Cheng TO: Transcatheter closure of patent foramen ovale: a definitive treatment for platypnea-orthodeoxia. Catheter Cardiovasc Interv 2000 Sep; 51(1): 120.

• Cujec B, Mainra R, Johnson DH: Prevention of recurrent cerebral ischemic events in patients withpatent foramen ovale and cryptogenic strokes or transient ischemic attacks. Can J Cardiol 1999Jan; 15(1): 57-64.

• Devuyst G, Bogousslavsky J, Ruchat P, et al: Prognosis after stroke followed by surgical closure ofpatent foramen ovale: a prospective follow-up study with brain MRI and simultaneous trans-esophageal and transcranial Doppler ultrasound. Neurology 1996 Nov; 47(5): 1162-6.

• Dubourg O, Bourdarias JP, Farcot JC, et al: Contrast echocardiographic visualization of cough-induced right to left shunt through a patent foramen ovale. J Am Coll Cardiol 1984 Sep; 4(3): 587-94.

Figure 1: Early peak of the PFO.

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If you’ve only scanned at 1.5T, you’ve never had to thinktwice about specific absorption rate (SAR). SAR is of particularconcern with 3.0T MR scanning, since the RF energy requiredto create an image at 3.0T is four times that required at 1.5T –which can limit the way some facilities scan.

On many 3.0T systems, techs may be forced to stop scanningto prevent the patient from becoming too warm. This canimpact scan time, total procedure time and patient tolerance.Ineffective SAR management can also limit slice coverage,requiring double acquisitions and longer scan times. All of

these factors will reduce throughput and productivity whilesacrificing patient comfort and convenience.

Regulated by the FDA and IEC, SAR is the amount of heat that can be dissipated into a patient during an MR procedure.Staying within these guidelines can be relatively easy whenworking with an MR manufacturer which has addressed SAR effectively.

GE’s Signa® 3.0T MR technologies make SAR less of an issue,even when scanning pediatric cases.

3.0T MR Imaging: SAR Managementwithout CompromiseBy Bryan Mock, Ph.D., Global 3T Product Manager, GE Healthcare

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T E C H N I C A L I N N O V A T I O N3 . 0 T S A R M A N A G E M E N T

PERFORM for SAR Management

With over a decade of 3.0T system evolution experience, GE Healthcare has overcome SAR challenges to deliver clinically relevant acquisition approaches, scan parameters,slice coverage and image quality at 3.0T. GE’s approach,PERFORM, is automated and available on the Signa HD 3.0TMR system, enabling facilities to reap the benefits of 3.0T MRimaging without giving SAR a second thought.

The end result of PERFORM is faster exams, greater produc-tivity, less technologist training, more comfortable patientsand better imaging results.

GE’s PERFORM optimized SAR management increases slicecoverage and reduces scan time – while eliminating theneed for patient cooling – for enhanced clinical productivityand increased patient comfort.

Real-time Power Monitoring and Reporting

Extremely accurate digital RF monitoring in real time calculates a patient’s total RF exposure on the fly – duringthe exam – no matter what body part is being scanned orwhat coil is used. At all times, the operator can maintain clinically relevant scan parameters without compromise.

Revolutionary Body Coil Design

Designed for high efficiency, the Signa HD 3.0T body coilrequires less RF energy to drive during high-field scanning.Therefore, the total heat deposited in the patient is reduced;all RF power is used for imaging and not wasted in patient heating.

GE’s Signa® 3.0T MR technologies make SAR less of an issue, even when scanning pediatric cases.



By blending GE’s breakthrough technologies, the SAR-optimizedSigna HD 3.0T system reduces patient RF exposure andheating and removes the burden of SAR management.

The unique PERFORM package integrates a range of GE-exclusive SAR-management technologies, offering amulti-faceted approach that ensures shorter scan times. The result is 1.5T-like slice coverage with more relevant TRs,TEs and flip angles.

PERFORM overcomes the SAR challenges of 3.0T andremoves limitations for MR imaging.

Signa HD 3.0T with PERFORM gives the necessary slice coverage along with shorter scan times and uncompromisedscan parameter selection, guaranteeing superb image quality across an entire patient population. �


Pulse-sequence Optimization

Through unique, optimized approaches to pulse sequencedevelopment, Signa HD 3.0T performs SAR-intensive scans –such as long train FSE and magnetization transfer prepara-tion – while maintaining clinically-relevant slice coverage.

GE’s proprietary RF management techniques – such asASSET parallel imaging, VERSE, MART and B1 optimization –are all standard on every Signa HD 3.0T system. Each isdesigned to unlock the full potential of 3.0T imaging by leveraging the higher signal-to-noise ratio (SNR) available at ultra-high field without compromises.

Some 3.0T systems may not be able to obtain the scanparameter required for all body weights in a patient population –and nothing has a greater impact on image quality. Only GEdelivers B1 optimization approaches that result in consistentimaging in every patient, every time, regardless of body weight.

T E C H N I C A L I N N O V A T I O N 3 . 0 T S A R M A N A G E M E N T

Figure 1. Lumbar Spine without VERSE Figure 2. Lumbar Spine using the GE SAR optimized VERSE option maintainsscan time while improving coverage.




T E C H N I C A L I N N O V A T I O NN E U R O – P R O P E L L E R H D

Motion artifacts in brain scans are caused by a variety offactors. They can result from “sightseeing” (a patient taking a random look around at the inside of the coil during a scan), gross motion from uncooperative patients or subtle physiologic motion. Whatever the cause, motion artifacts in brain scanning are a chronic problem. In fact:

• Approximately four in every 10 brain exams show sometype of motion artifact. Approximately one in 10 have to be rescanned.

• One in six pediatric patients don’t respond adequately to sedation. One in 14 don’t respond at all.

PROPELLER HD Gives a New Spin on the Old Problem of Artifacts

Short of administering some sort of sedative, it seems that motion artifact in head imaging is unavoidable.

GE Healthcare’s introduction of PROPELLER™ HD (PeriodicallyRotated Overlapping ParallEL lines with Enhanced Reconstruction)has significantly reduced the effects of motion artifact in routine T2 and T2 FLAIR scanning of the brain.

PROPELLER HD is available on the HD upgrade for GE Healthcare’s Signa MR systems.

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An example of PROPELLER HD’s ability to reduce motion artifactin T2 FLAIR imaging is seen in Figures 1 and 2. The FSEimage in Figure 1 was obtained from an uncooperativepatient. Clearly, the image is diagnostically useless.

Figure 2 was obtained from the same patient and acquiredusing the PROPELLER T2 FLAIR, reducing any artifact from motion.

These images demonstrate that PROPELLER HD can make a substantial difference in scanning situations where patientmotion cannot be adequately controlled.

PROPELLER HD in T2 and T2 FLAIR imaging reduces bothgross- and subtle-motion artifacts. With PROPELLER HD diffusion weighted imaging (DWI), there is less visible artifactfrom dental work or other metal, along with less posteriorfossa susceptibility. PROPELLER HD also enhances contrast-to-noise ratio (CNR), contrast interfaces and lesion conspicuity.

T E C H N I C A L I N N O V A T I O N N E U R 0 – P R O P E L L E R H D

PROPELLER HD DWI addresses a major cause of artifacts in brain imaging – susceptibility. This versatile sequenceimproves image quality in the vicinity of bone/tissue orair/tissue interfaces, or around tissue/metal interfaces proneto creating susceptibility artifacts. PROPELLER HD DWI’s capacityto suppress susceptibility artifacts can be particularly helpful in stroke evaluation.

Since there is a considerable amount of data to process,PROPELLER HD uses intensive multi-channel image recon-struction and processing techniques. It also uses five timesmore processing steps than a conventional DWI acquisition.

After the initial signal is obtained, PROPELLER HD executesFSE phase correction to produce images virtually free of the susceptibility artifacts typically seen in images of patientswith significant amounts of dental or other metals close to the region of interest.

Figure 1Motion artifacts can set a scanning scheduleback significantly. This is a T2 FLAIR image of an uncooperative patient.

Figure 2 Image obtained on the same patient using the PROPELLER HD T2 FLAIR Pulse Sequence.




T E C H N I C A L I N N O V A T I O NN E U R O – P R O P E L L E R H D

PROPELLER HD T2 Imaging

In a process similar to that undertaken with PROPELLER HDDWI imaging, a customized screen displays only the factors pertinent to PROPELLER HD T2. The user then selects TR andecho train and center frequency. PROPELLER HD T2’s radialacquisition technique enhances CNR, significantly improvingcontrast interfaces and lesion conspicuity. With high-definitionMR, tailored RF eliminates signal variation in early echoesand reduces SAR and echo spacing, providing more sliceswith less blurring and shorter scan time.

PROPELLER HD T2 FLAIR Imaging

PROPELLER HD T2 FLAIR imaging provides robust T2W imagingwith CSF suppression. With CSF suppressed, there is bettervisualization of gray and white matter.

Again, much like the process with PROPELLER HD DWI and PROPELLER HD T2, a special window appears when selectingPROPELLER HD T2 FLAIR, with a minimum TR of 8000, TI is automatically calculated based on TR/4. �

The left image demonstrates the typical susceptibility effects seen with EPI-based Diffusion WeightedImaging (DWI) of the skull base. With the elimination of susceptibility artifact from the skull base (rightimage), a temporal lobe infarct is clearly demonstrated. Without PROPELLER HD DWI, the infarct couldnot be differentiated from the artifact.

Notice how much sharper the gray/white matter interface is in the PROPELLER HD T2 image (right) ascompared with the FSE T2 (left). PROPELLER HD T2 produces higher resolution in equal or less scan timethan conventional T2 imaging. Compare white matter detail in these two images for both conspicuityand edge sharpness.

Figure 3 Figure 4

Figure 5 Figure 6



during various task-related events (active state), localincreases in vascular behavior, in response to increasedmetabolic activity in these areas, produces a relativedecrease in the resting concentration of deoxygenated blood.This increases local T2* characteristics, which produces aslight increase in MR signal amplitude when imaged with the same echo time as the resting state. The signal increasesare very small, between one and three percent for 1.5T andthree and five percent for 3.0T (due to improved signal-to-noiseratio [SNR] and more pronounced T2* effects). To extract thissmall signal change from noise levels that may exceed thesmall percentages, the experiment is repeated a preset num-ber of times, alternating between active and rest states, untilenough signal averaging can be detected with statisticalmethods to delineate with statistical confidence regions ofincreased signal due to activation. This type of experiment is known as a block design.

With sufficient signal to noise and appropriate processingmethods, event designs are also popular, where singular ormultiple events are presented during the course of continuousimaging, often yielding a more global transitory or dynamicresponse. The BOLD effect has been the subject of significantinvestigation and controversy,5 since the vascular responseon the order of seconds is delayed relative to the neuronalactivations on the order of milliseconds. Yet, fMRI using BOLDcontrast is today’s most popular method for visualizing brain activation.


Abstract

As the pace of clinical MR procedures grows, advancedapplications are increasing at a faster rate than traditional(morphologic) exams. This often occurs despite financialobstacles, such as lack of reimbursement, because theadvantages of a new procedure or process to the patientoutweigh the financial constraints. However, essential to theclinical deployment of new procedures is a useful toolset for the clinician, which makes these applications practical for clinical use rather than just research.

Functional magnetic resonance imaging (fMRI) is one suchgrowth application that has the potential for immediateimpact on patient treatment1 despite the current lack ofaccredited reimbursement. It is incumbent upon the majorMRI equipment manufacturers to provide a credible set oftools that allow the clinical radiologist, with a minimalamount of technical support, to produce accurate functionalbrain activation maps in as short of exam time as possible,ideally within the current limits of traditional exam time slots.The GE BrainWave™ package for Signa™ HD MR scanners isone such commercial toolset for performing clinical fMRI.

Introduction

fMRI has its beginnings in basic MR science, where the phe-nomena of blood-oxygen level dependent (BOLD) contrastwas first understood2. This well-documented model3,4 isbased on the theory that as regional brain activation occurs

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Functional Magnetic Resonance Imaging:Tools for the Clinical SettingBy Josef Debbins Ph.D., Bryan Mock Ph.D. and Heidi Ward, Ph.D.

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T E C H N I C A L I N N O V A T I O NF U N C T I O N A L M A G N E T I C R E S O N A N C E I M A G I N G

The BrainWave Package

The architecture of GE’s BrainWave package is divided intofour major components.

a. BrainWaveRT is a primary real-time application (user interface, pulse sequence and reconstruction) for acquiringhigh quality fMRI data sets and includes a ParadigmManager for synchronizing pulse sequence timing to desired paradigm timing.

b. BrainWavePA is an additional data post-processing and analysis package for creating activation maps and clinical presentation.

c. BrainWaveHW Lite is a separate computer system for creating and generating visual and audio paradigmsthrough standard audio and visual output. The systemalso includes patient response key pads for deliveringresponse signals back to the system for display on theacquisition user interface. Paradigms are automaticallyqueued and sequenced with the BrainWaveRT data acquisition.

d. Delivery equipment takes the video and audio outputsfrom BrainWaveHW Lite or other paradigm source into the patient (magnet) environment. This market is presentlyserved by various third-party companies.

The base required component on Signa HD 1.5T and 3.0T MRscanners is BrainWaveRT, which is responsible for high-qualitydata acquisition and paradigm timing. BrainWavePA is an optional package for rapid data analysis and clinicalpresentation, while BrainWaveHW Lite is an optional package for paradigm creation and generation.

Figure 1 shows the software components – BrainWaveRTand BrainWavePA – as hosted by the scanner (left) andoptionally using BrainWavePA on GE’s Advantage Workstation(right). Note that in research mode, BrainWaveRT can additionally provide raw (k-space) data written directly to a flat file (Pile) for subsequent off-line research analysis if desired.

Figure 2 depicts the connection between BrainWaveRT andthe paradigm generation software (NeuroActivator) runningon BrainWaveHW Lite. Queuing and synchronization eventsare handled over Ethernet, while translation of paradigmtiming to the pulse sequence play out is done using a “paradigm protocol” created by the Paradigm Manager.

Figure 3 demonstrates how the BrainWaveHW Lite paradigmgeneration computer can be connected to third-partydevices to deliver the audio and video stimulus to the patientsetting. Standard video (SVGA DB15) and audio (1/8th inchstereo jack) outputs are provided on BrainWaveHW Lite to interface with these as well as custom “home-built” delivery systems.

Figure 1. BrainWave Architecture Figure 2. BrainWaveRT invoking BrainWaveHW Lite Figure 3. BrainWaveHW Lite coupled to third-partydelivery devices




Experimental Considerations

Setup and Control of Experiment: When performing an fMRI experiment, rapid and predictable setup and control is paramount to success. When implemented with theBrainWave package, fMRI achieves this goal by leveraging thefamiliar and technologist-friendly practice of using protocolsto drive the scanning applications. BrainWaveRT, the primaryscanning application, is no different, using a modified EPIpulse sequence to acquire the image data sets for fMRI.Scan parameters such as geometry, timing and resolutionare loaded from an existing protocol in the traditional fashionas morphological imaging scans. The scan protocol thatloads BrainWaveRT also invokes a “paradigm protocol” calledout by name, such as “Dr. Johnson #6 visual” or “bilateralmotor.” The paradigm protocol consists of specialized fMRIparameters used to define the timing of the paradigm delivery.For example, the total number of phases (acquired samples),the number of on and off cycles for a block design or thenumber of dummy repetitions are set in the paradigm protocol.Repetition time (TR) is set in the paradigm protocol since itcontrols sampling density and block design scan timing and,indirectly, slice count in the traditional imaging protocol. A Paradigm Manager creates and edits new and existing paradigm protocols that can be used with the EPI pulsesequence to acquire accurately timed and synchronized data.

Paradigm Development: Development of paradigms generallyoccurs in an off-line fashion – the experiment is designedahead of time and typically audio and visual inputs are provided to the patient at appropriate time points in the data acquisition. To sequence these audio and visual queues,software was developed to facilitate this. Several commercialpackages include ePrime, Presentation and NeuroActivator.These software tools permit the user to input JPEG, TIFF andWAV files (among other standardized file formats) andsequence them with timing coinciding with data collectionby the MRI scanner. The GE BrainWaveHW Lite package usesNeuroActivator in research mode for paradigm development.However, other paradigm development tools have been usedand successfully synchronized (using available scanner triggerpulses) with the BrainWaveRT acquisition pulse sequence inthe absence of BrainWaveHW Lite. The BrainWave packagewas specifically designed to accommodate alternative methodsof paradigm development and delivery.

High-quality Data Acquisition: After the fMRI protocol isloaded, the system will pre-scan the EPI pulse sequence andlaunch the dedicated BrainWaveRT user interface in a standby

mode. If used with the BrainWaveHW Lite paradigm, thecomputer will be queued to load and ready the desired paradigm. If using alternative delivery means, the paradigmcan be queued at this time. The operator can then providefinal verbal instructions to the user before initiating an fMRIparadigm scan or run. A typical block run is two to six minutesand runs can be repeated for conjugate analysis of results oraltered to obtain different activation results (i.e. motor vs. verbal).

During acquisition, the generated EPI data sets, acquired at frame rates of up to 25 frames per second (fps), are continuously reconstructed and streamed to the scannerdatabase in DICOM format. Up to 20,000 images can beacquired in a single run. Four non-phase encoded echos areplayed out for each TR with phase correction performed on thefly, which compensates for subtle changes in gradient areaover time, further minimizing ghosting. The paradigm name is stamped into the DICOM header for use in subsequentanalysis and visualization. In the research mode, theresearcher can lock the k-space data into a flat file for offline analysis.

Next, on-the-fly statistical analysis tools create 2D color activation maps based on a statistical threshold set by theuser. The size of the activation smoothing filter can be userset as well. A data quality algorithm monitors SNR, ghostingand patient motion, and presents results on-the-fly with asimple green-yellow-red “traffic light” presentation. If presetlimits are exceeded, the operator can stop the scan andcoach the patient to assure high quality EPI data. Time-activitycurves can be plotted. High-resolution 2D anatomical imagescan be imported as background images to the color activationmaps. Any activation image viewed can be DICOM secondarycaptured to the scanner database in color. Figure 4 depictsthe complete BrainWaveRT user interface designed for atechnologist in a clinical setting.

Paradigm Play-out and Synchronization (during data acqui-sition): As depicted above, timing parameters to successfullyqueue and synchronize the actual delivered stimulus (audioand visual) are critical. Thus, TTL pulses are provided to paradigm generation hardware to start the queued paradigm.Pulses can initiate the paradigm and provide dedicated control of each on/off cycle transition.

Data Analysis: Following data acquisition, any number of toolscan be used to analyze the acquired EPI data set. These includeAFNI and SPM, among others. The BrainWavePA package

T E C H N I C A L I N N O V A T I O N F U N C T I O N A L M A G N E T I C R E S O N A N C E I M A G I N G




permits rapid, on-line analysis and visualization of the activation maps, fused with high-resolution 3D segmented (if desired) anatomical data. Figure 5 depicts BrainWavePAafter it renders activation, which is a available a few minutesafter completing data acquisition.

BrainWavePA will first do a registration pass to correct forminor displacements of the EPI data sets due to subtlepatient motion. After calculating the activation maps usingpartial correlation or simple t-testing, the user can choosewhich maps to fuse and visualize. Threshold and filtering levels can also be adjusted. All rendered images, including3D reformats with color activation, can be DICOM secondarycaptured to the scanner database. BrainWavePA is alsoavailable for Advantage Workstation 4.2 Linux workstationsfor off-scanner data analysis and visualization.

Clinical Presentation: Of significant interest to clinicians or surgeons are the regions of activation as rendered onanatomical images as shown in Figure 5 with BrainWavePA.Additional useful image sets provided by BrainWavePA arethe full DICOM fidelity burned in pixel maps. These maps,whether segmented or not, burn the regions of activation ashot white into a copy of the DICOM 3D data sets. These datasets, with full DICOM geometry fidelity (like they werescanned), can be used to drive third-party, DICOM-compatibleneurosurgery equipment (BrainLab, Stealth, etc.). The abilityto screen capture, network, archive and print any image produced by BrainWaveRT or BrainWavePA becomes a powerful tool in the clinical arena and a complimentarycollection and analysis package in the research setting.

Future Directions: The BrainWave platform on Signa™

is expected to be the springboard for additional future functionality development. Patient motion can often defeatfMRI experiments6,7. Using prospective motion correction8,9, in particular orbital navigators9-11, for on-the-fly correction

is part of the BrainWave roadmap. Paradigm support forevent-related experiments is a planned enhancement to theBrainWave package. Ultimately, packaging the fMRI resultsto the clinician in an easy-to-use, easy-to-read summary will be a key component toward clinical acceptance andfuture reimbursement.

Summary: BrainWave is a powerful and easy-to-use clinicalfMRI package, available to-day on GE Signa HD MR scanners.Research components have been built in to service the largefMRI research community. Optional paradigm developmentand generation hardware is available, offering a completeand flexible fMRI package to the clinical and research MR community. �

References

1. Volkow, ND, Fowler, JS, Wang, GJ. The addicted human brain: insights from imaging studies. The Journal of Clinical Investigation, 2003: 111:1444-1451.

2. Belliveau JW, Kennedy DN, McKinstry RC, Buchbinder BR, Weisskoff RM, Cohen MS, Vevea JM,Brady TJ, Rosen BR. Functional mapping of the human visual cortex by magnetic resonance imaging. Science 1991;254:716-719.

3. Bandettini PA, Wong EC, Hinks RS, Tikofsky RS, Hyde JS. Time course EPI of human brain functionduring task activation. Magn Reson Med 1992;25:390-397.

4. Kwong KK, Belliveau JW, Chesler DA, Goldberg IE, Weisskoff RM, Poncelet BP, Kennedy DN, HoppelBE, Cohen MS, Turner R, Cheng HM, Brady TJ, Rosen BR. Dynamic magnetic resonance imaging ofhuman brain activity during primary sensory stimulation. Proc Natl Acad Sci USA 1992;89:5675-5679.

5. Ogawa S, Tank DW, Menon R, Ellermann JM, Kim S, Merkle H, Ugurbil K. Intrinsic signal changesaccompa-nying sensory stimulation: Functional brain mapping with magnetic resonance imaging.Proc Natl Acad Sci USA 1992;89:5951-5955.

6. Hajnal JV, Myers R, Oatridge A, Schwieso JE, Young IR, Bydder GM. Artifacts due to stimulus correlated mo-tion in functional imaging of the brain. Magn Reson Med 1994;31:283-291.

7. Friston KJ, Williams S, Howard R, Frackowiak RSJ, Turner R. Movement-related effects in fMRI time-series. Magn Reson Med 1996;35:346-355.

8. Lee CC, Jack CR, Grimm RC, Rossman PJ, Felmlee JP, Ehman RL, Riederer SJ. Real-time adaptivemotion correction in functional MRI. Magn Reson Med 1996;36:436-444.

9. Lee CC, Grimm RC, Manduca A, Felmlee JP, Ehman RL, Riederer SJ, Jack CR. A prospectiveapproach to correct for inter-image head rotation in fMRI. Magn Reson Med 1998;39:234-243.

10. Fu ZW, Wang Y, Grimm RC, Rossman PJ, Felmlee JP, Riederer SJ, Ehman RL. Orbital navigator echoesfor motion measurements in magnetic resonance imaging. Magn Reson Med 1995;34:746-753.

11. Ward HA, Riederer SJ, Grimm RC, Ehman RL, Felmlee JP, Jack CR Jr. Prospective multiaxial motioncorrection for fMRI. Magn Reson Med 2000;47:32-41.

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Figure 4. BrainWaveRT user interface as launchedduring fMRI data acquisition

Figure 5. BrainWavePA rendering motor activationon 3D structural data set

Volume Rendering View

Main Menu Bar

Control Panel

Image Display Views

Message Area Progress Area



T E C H N I C A L I N N O V A T I O N V A S C U L A R – T R I C K S

Peripheral Vascular MR AngiographyBy Stuart Clarkson, MR Cardiovascular Applications Product Manager, GE Healthcare

In the United States, over 10 million people suffer from peripheral vascular disease,including 5 percent of the population over the age of 50. Peripheral vascular disease is a condition in which the peripheral arteries are narrowed causing a decrease in the volume of blood supplying the limbs, most commonly the legs.

The major cause of Peripheral Vascular Disease is atherosclerosis.

Atherosclerosis comes from the Greek words athero (meaning gruel or paste) and sclerosis (hardness). It’s the name of the process in which deposits of fattysubstances, cholesterol, cellular waste products, calcium and other substancesbuild up in the inner lining of an artery. This buildup is called plaque.

People with a family history of premature cardiovascular disease have an increasedrisk of atherosclerosis. These risk factors can’t be controlled. However research1

shows the benefits of reducing the following controllable risk factors for atherosclerosis:

• High blood cholesterol (especially LDL cholesterol over 100 mg/dL)

• Cigarette smoking and exposure to tobacco smoke

• High blood pressure

• Diabetes mellitus

• Obesity

• Physical inactivity

Current state-of-the-art MR Angiography involves a bolus chase technique of an intravenously administered Gadolinium-based contrast agent with excellent visualization of the lower limbs. However, the distal vasculature is often inadequately imaged due to signal-to-noise limitations despite the use of local phased array coils.

With the advent of higher RF channels, the technology to build a receiving coil to greatly enhance the signal-to-noise ratio (SNR) for lower limb vascular imagingnow exists. A peripheral vascular (PV) coil utilizing 32 elements is proposed toincrease the SNR for lower leg MRA by a factor of no greater than 12 compared to the Body T/R coil. Such a dramatic SNR improvement is expected to enablescanning at much higher resolution than currently available techniques.

Signa HD Lower-Leg Array

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By performing a 3D TRICKS™ (Time Resolved Imaging withContrast Kinetics) acquisition in a sagittal scan plane, ratherthan the conventional coronal, the lower limb vasculature fromtrifurcation to dorsal pedal arch can be covered with a smallernumber of slices and therefore improve temporal resolution.

By performing a sagittal scan for the vascular anatomy, a single leg may be imaged per injection. GE has developed a novel SWIFT™ (SWItch on The Fly Technique) approach toenable bilateral lower leg imaging during a single contrastinjection while maintaining the sagittal 3D slice orientationfor the acquisition.

SWIFT utilizes a fast switch that enables reception of signalfrom either the right or left PV Coil alternately. This ‘switch onthe fly’ technique images in conjunction with alternating TR’swhich excite the left leg with one TR, then the right leg withone TR and back and forward until all the phase encoding stepsfor both legs are completed and the images are reconstructed.

SWIFT is useful for imaging two distinct volumes simultaneouslyand has the added benefit of doubling the SNR due to theeffective doubling of the TR for each volume. The drawbackof SWIFT is the doubling of the scan time. This may be problematic with TRICKS imaging as it is desirable to maintain repetition of the 3D volume in under 10 seconds.

T E C H N I C A L I N N O V A T I O NV A S C U L A R – T R I C K S

With the desire of performing at least 60 thin slices per leg in the 3D volumes, temporal resolution becomes the challenge with SWIFT.

To half the temporal resolution,TRICKS may be implemented withthe parallel imaging technique ASSET™ (Array SpatialSensitivity Encoding Technique),thereby easily maintaining sub 10 second temporal resolution.

As may be seen in the figure onthe left, exquisite depiction of thethree major vessels of the lower limb, in addition to the dorsalis pedis arch, is shown in one phase from the multiphase. TRICKS with ASSET was used at 34 seconds post IV injection of the contrast agent.

Bolus chase MRA with Image Pasting 12cc Gd injection demonstratingvisualization of the vessels of thelower limb.

Positioning of the scan field of view in the sagittal (oroblique/sagittal) plane.

Parameter Input

Scan Plane Obl Sagittal

TR 6.1 ms

TE 1.7 ms

Bandwidth 42 kHz

Matrix 512 x 512

Slice thickness 1.2 mm

Number of Phases 12

Temporal Res 9 sec per phase

ASSET Factor 2 (in phase dir)

Reference:

1) American Heart Association published data. http://www.americanheart.org/presenter.jhtml

Summary

SWIFT enables the use of 32 element coil technology on 32, 16 or 8 channel MR systems, ensuring all elements of the coil are scanned with a single field of view.

A novel approach to improved PV MR Angiography is proposed with high density element coils and the SWIFT 3Dimaging technique. �

PV Study parameters of TRICKS with ASSET Scan.

Popliteal

Peroneal

Pedal arch

Anteriortibial

Posteriortibial

Dorsalispedis

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MRI provides critical data such as high-resolution 3D imagingof the tumor and internal organs. It also provides real-timetemperature feedback that indicates the degree of tissueheating and coagulation. This integration of FUS with MRIprovides a “closed-loop therapy and feedback system” thatenables the physician to adjust treatment parameters andcontrol the treatment, helping to ensure a high level of safetyand efficacy.

Fibroids are benign growths in the uterus, which are symptomatic in 25 to 40 percent of women of childbearingage. Symptoms can include heavy and prolonged bleeding,severe pain, bloating and constipation or urinary complaints.

The most common treatment is hysterectomy, a highly invasive surgical procedure to remove the uterus, which is associated with the usual surgical risks and complications,requires a three- to four-day hospital stay and results inpatient recovery time of six weeks or more.

All other techniques involve some level of incision, hospitalization and recovery time. For example, myomectomyrequires a hospital stay of several days and recovery time of two to four weeks.

In contrast, the non-invasive MRgFUS technology is associatedwith minimal risks and complications, requires no overnighthospital stay and allows most patients to return to work and their normal activities in one to two days.

In Phase III trials, patients treated with the ExAblate 2000 systemmissed 1.4 working days, on average, compared to 18 daysfor hysterectomy patients. They returned to normal activity in less than three days, compared to 17 days for hysterectomy patients.

Abstract

Magnetic Resonance guided focused Ultrasound (MRgFUS) is gaining popularity as an alternative to medical and surgicalinterventions in the management of symptomatic uterinefibroids. Studies have shown that it is an effective non-invasivetreatment with minimal associated risks as compared tomyomectomy and hysterectomy.

In this report, we present a case of a patient treated at theSheba Medical Center in Tel Aviv using the ExAblate® 2000 to perform non-invasive MRgFUS for a symptomatic uterinefibroid. This treatment resulted in a significant improvementin the patient’s symptoms.

Introduction

MRgFUS is a revolutionary non-invasive technology for thermal ablation of fibroid tumors. In contrast to invasivetreatments for uterine fibroids, the completely non-invasiveMRgFUS can be performed as an outpatient procedure andrequires no anesthesia.

ExAblate 2000 (InSightec Ltd., Haifa, Israel) is the first deviceto combine magnetic resonance imaging (MRI) with high-intensity focused ultrasound to destroy tumors non-invasively.ExAblate works exclusively with GE Healthcare's Signa® HD1.5T MR system.

ExAblate uses a ‘sonication’ process wherein focused ultra-sound (FUS) destroys tissues by concentrating a high-energybeam on a specific point and raising its temperature to 60°to 80°C. Multiple sonications are required to ablate a specific tissue.

T E C H N I C A L I N N O V A T I O N M R G U I D E D F O C U S E D U LT R A S O U N D

New Non-Invasive Treatment Option for Uterine Fibroids Using Signa 1.5T and MR Guided Focused UltrasoundBy Yael Inbar, MD, Director of MR guided Focused Ultrasound Unit, Sheba Medical Center, Tel Hashomer, Tel Aviv, Israel



Prior to treatment start, 100mg Voltaren, 2mg Dormicom, 70 mg Pethidine and 10 mg Pramin were administered to the patient.

Treatment Planning

The patient was placed in the MRI scanner.

T2 weighted MR images of the pelvis were acquired andused to define the fibroid volume to be ablated. The systemautomatically calculated a treatment plan, made up of a series of sonications (focal delivery of energy) to cover theregion of treatment (see Figure 1). Each spot is cylindricallyshaped, 30 to 45mm in length and 5mm in diameter.

Figure 1 also shows the sonication beam path, which is carefully checked to ensure that it does not pass throughany structures that should be avoided – such as the smallbowel that can fall in front of the uterus.

In addition, special markers were defined on image contoursto help detect patient movement during treatment.

Patient

A 52-year-old woman, gravida 2, presented with menorrhagiadue to fibroids. The size of her uterus was the equivalent of a17-week pregnancy. Ultrasound revealed uterine irregularity,with individual fibroids as large as seven to eight cm. Shealso has fibromas in the posterior vaginal wall. She suffersfrom high blood pressure and is treated with Normiten. She was otherwise healthy, without prior significant medicalhistory or surgeries.

In pre-treatment MR screening, she was found to have oneposterior intramural fibroid, 10.3 X 10.9 X 10 cm in size,hypo-intense in comparison to the uterine wall on T2Wimages, and enhancing on contrast enhanced T1W images.The fibroid was found to be accessible to the ultrasonic beam(no bowels, bones or other obstacles in the area of the fibroid).

Patient Preparation

The patient’s abdomen was shaved and cleaned. A urinarycatheter was inserted to prevent uterine movement duringthe three-hour treatment. An IV line was inserted for sedationadministration and the patient's legs were wrapped withcompression stockings. The patient was positioned on theExAblate treatment table with her abdomen over the waterbath containing the ultrasound transducer.



Results

Immediately following treatment, the patient expressed satisfaction with the treatment.

On the day following treatment, she was able to return to her normal activities with no unusual events and no medication. At her one month follow up, the patient reportedthat her symptoms almost completely disappeared.

Summary

MR guided focused Ultrasound provides an important newnon-invasive and effective treatment for uterine fibroids.Recovery from the treatment is almost immediate and symptom relief is generally felt quickly. This is a tremendousadvantage over existing options, which place a large burdenon patients.

Additional applications are under investigation and holdthe promise of transforming the surgical arena to benefitmillions of patients. �

Treatment

Before treatment, one low energy 'verification' sonicationwas delivered to ensure that the actual target spot was inthe planned target location. Actual treatment consisted of 73 sonications producing thermal lesions (spots) within thedefined target area to produce ablated tissue. Each sonicationwas 20 to 30 seconds, followed by a 90 second cool downperiod. Thermal feedback generated by real-time PRF andmagnitude images highlighted the temperature and theanatomy in the targeted area. A temperature graph showedthe temperature change on the temperature maps. The system automatically highlighted the treated areas in blue(see Figure 2).

Sonication parameters can be changed if necessary, includingpower, duration, spot size and frequency.

After all the sonications were completed and the dose volumewas determined to be adequate for fibroid destruction, treatment ended. Post-treatment contrast enhanced T1weighted images were acquired to immediately determinethe treatment outcome. These images showed that thetreated fibroid was mostly non-enhancing (see Figure 3).

Following treatment, the patient remained in the hospital for one hour to recover from the sedation and then wasreleased home.

T E C H N I C A L I N N O V A T I O N M R G U I D E D F O C U S E D U LT R A S O U N D

Figure 3 – Sagittal T1w+C post treatment MR images showing the fibroidalmost totally non-enhancing.

Figure 2 – Treatment screen showing the real time temperature maps withthermal dose (upper row) and magnitude anatomical images (middle row).The real time temperature graph (lower right) shows the temperature rise in the focus of the spot.

Figure 1 –The treatment plan: coronal (upper row) and sagittal (lower) viewof the sonication spots overlay on the T2w planning images.

MRgFUS is for women who do not wishto become pregnant in the future.



Wrist and Cervical-Thoracic-Lumbar (CTL) Spine – and higherchannel count coils such as the 12-Channel Body Array andthe 16-Channel Lower Leg Coil Array.

The HD Head-Neck-Spine Array is the very first multi-site coildesigned for convenience without compromise. This 16-Channelcoil with 29-targeted elements for the brain and spine minimizes coil changes for most procedures within the typical MR department. By replacing three current coils –Head, Neurovascular and CTL – with a single, combined

GE Healthcare recently introduced the Signa® High-Density(HD) Head-Neck-Spine Array Coil that revolutionizes MRimaging as we know it today. The Head-Neck-Spine ArrayCoil utilizes industry-leading RF technology and an advanceddesign that places the highest density of coil elements in theimaging field of view. This revolutionary design increases signal to noise, facilitates patient throughput and optimizesimage quality for greater diagnostic confidence and patientcomfort. The 16-Channel HD Head-Neck-Spine Array furtherexpands GE’s HD coil portfolio, which includes multiple 8-Channel coils – Neurovascular, Body, Cardiac, Brain, Knee,

T E C H N I C A L I N N O V A T I O NH I G H - D E N S I T Y C O I L S

Complete Brain andSpine Imaging WithoutCoil Changes

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Key features of the HD Head-Neck-Spine Array include:

• 2D parallel imaging in any plane or scan orientation in the brain;

• PROPELLER HD compatibility for motion-insensitive imaging with no time penalty – even in pediatrics;

• Support of all scanning modes – including anatomical/vascular, spectroscopy and fMRI;

• Full coverage for total spine studies.

The Signa HD Head-Neck-Spine Array further demonstratesGE’s leadership in High Density coil technology, our commitmentto patient comfort and our desire to improve outcomesthrough advanced technology and design. �

T E C H N I C A L I N N O V A T I O N H I G H - D E N S I T Y C O I L S

coil, the HD Head-Neck-Spine Array reduces redundant coilswitches by over 50 percent in studies that, on average,account for 71 percent of the procedural volume in the typical MR unit.

One example of the benefits of this coil can be realized during a typical spine survey. During this exam patients arerepositioned up to three times using multiple coils, whichinterrupts the scanning process each time and significantlyincreases the scan length. This is more than an inconvenienceas most patients are given contrast prior to the exam andthe time lost due to coil switches and repositioning mayrequire additional injections be administered. The HD Head-Neck-Spine Array allows one coil to be placed on the table toimage multiple anatomical areas without moving the patientor switching coils, reducing patient table time, increasingpatient comfort and minimizing the need for multiple injections.

The HD Head-Neck-Spine Array is a simple modular designthat allows the individual head, neck and spine sections tobe used together as a single, integrated unit for completehead and spine studies, or separately for individual studies.The thoracic and lumbar portion of the HD Head-Neck-SpineArray can be left on the table during most other exams tominimize coil changes and maximize patient throughput.

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B E Y O N D T H E S C A NE D U C A T I O N

Ongoing advances in GE Healthcare MR imaging technologycontinually increase the capabilities of GE MR products.Faster computers, more advanced protocols and magnetupgrades allow unprecedented imaging techniques. Withproper training in these latest applications and software, a site will be able to draw on the full potential of its MR scanner. As a result, GE pioneered the creation of specialized education to enable physicians to fully utilize their MR equipment.

A unique offering of GE Healthcare, the MR Masters Series is designed to give physicians an avenue to learn about thelatest MR techniques — techniques that can help them todeliver better patient care while maximizing productivity.

Learn with ExpertsAt a network of GE MR training centers located throughoutthe United States, some of the world’s top radiologists trainphysicians from around the globe on how to maximize theclinical benefits of the most advanced MR techniques.

Offered throughout the year, each MR Masters Series courseis taught by a renowned radiologist who has mastered spe-cific procedures that maximize a particular MR application.After participating in a MR Masters Series course, physicianswill be fully equipped with the knowledge and skills neededto utilize new applications in their own facilities. Attend threeGE MR Masters Series courses and receive certification ofyour accomplishment. The GE MR Masters Series is fullyaccredited for CME credits.

See the next page for a summary of this year’s MR MastersSeries courses.

The GE Healthcare MR Masters SeriesHelps Clinicians Achieve Maximum Results

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B E Y O N D T H E S C A N E D U C A T I O N

Advanced High Field MR Practicum: 3.0T – 1.5TWith Lawrence N Tanenbaum MD FACR

This course will cover essentials and advanced diffusionimaging at 3.0T and 1.5T; mastering FSE; optimizing MR scanning with ASSET, PROPELLER HD and TRICKS; clinical spectroscopy; core protocol design for neuro, MSK and body;basic principles, applications of MRA; new MRA techniques;MR contrast agents and issues in neuroimaging at 3.0T and 1.5T; MR of the spine; image processing and display;scanning on the Signa interface; and managing anadvanced imaging practice.

Clinical fMRI at 1.5T and 3.0T With Keith Thulborn, M.D., Ph.D., Chicago, IL

This two-day course provides integrated didactic lecturesand hands-on training for brain imaging on the 1.5T and 3.0TSigna LX scanners. Emphasis is on functional imaging protocolsusing diffusion and blood oxygenation level dependent(BOLD) contrast. Conventional anatomic and angiographicsequences at both field strengths will be compared in clinical application.

Cardiovascular MRIWith Steven D. Wolff, M.D., Ph.D.Course Co-Director Cindy R. Comeau, BS, RT (N) (MR)

This three-day weekend workshop focuses on cardiac MRI and vascular MRA with didactic lectures, small group tutorials,case reviews and hands-on time to scan human volunteers.

Musculoskeletal Imaging – Applications, Techniques andInterpretation with Emphasis on Joint Imaging With Michael Zlatkin, M.D., Timothy Sanders, M.D. and Paul Clifford, M.D.

This two-day short but comprehensive course will cover MR Arthrography, injection techniques, application and interpretation of joints. It includes overviews on MR techniquesfor coils, pulse sequences/parameters and for certain anatomyimaging such as wrist and ankle and foot. Protocols for MRArthrography, Meniscal Disorders as well as a variety of bodyparts – from rotator cuff to the hip – plus a special focus onbone and soft tissue tumors is covered as well. �

Physics and Clinical Applications With William G. Bradley, MD., Ph.D., FACR, San Diego, CA

Attendees will understand the physics behind MRI, when gradient echo, conventional spin echo, fast spin echo (FSE)and echo planar imaging (EPI) should be used, the major applications of MRI and know when MRI is preferred to CT.

Understanding and Applying Clinical MR Physics With Emanuel Kanal, M.D., FACR, Pittsburgh, PA

This five-day course is designed to give the attendee a deeperunderstanding of the basic physics and contrast mechanismsunderlying the MR imaging process and how to apply themto a busy clinical practice. It also provides a thoroughoverview of MR angiography, diffusion weighted imaging,perfusion weighted imaging, parallel, multichannel imaging,such as ASSET techniques and literally dozens of other clinical imaging techniques and parameters.

Breast MR Imaging With Constance D. Lehman, M.D., Ph.D., Seattle, WA

This comprehensive, practical and interactive 1-day course isdevoted to breast MRI and includes lectures on the technicalaspects of performing breast MRI with VIBRANT™, clinical indications for breast MRI, practical guidelines for interpretationof breast MRI and hands-on training interpreting clinicalbreast MR cases.

Beyond MRI: MR Spectroscopy for the New Millennium With Dr. Brian Ross, M.D. and Alexander Lin BS, Pasadena, CA

This course provides fundamental information necessary to use and interpret MRS and includes diagnostic examplesthat describe the clinical utility of MRS and its impact onpatients.

2006 Masters Course Overview

For complete faculty biographies, course description, location and dates for 2006, please visit the GE Healthcare website at: www.gehealthcare.com/usen/mr/education/products/physiciantrain.html

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B E Y O N D T H E S C A ND E F I C I T R E D U C T I O N A C T

imaging procedures imposed by the Deficit Reduction Act of2005; expansion of the multiple imaging procedure paymentdiscount policy; application of the Stark Law to Nuclear Medicineservices (including PET); and revisions to Medicare’s practiceexpense calculations.

GE Healthcare is committed to providing its customers withaccurate, reliable and timely information to help you navigatethese changes and prepare for emerging developments. We urge you to visit our reimbursement website atwww.gehealthcare.com/reimbursement for up-to-date information and analysis.

Here are some of the features you’ll find on the website (See Table 1). As always, your GE Healthcare AccountRepresentative is available to assist you as well. �

At GE Healthcare, we recognize the significant impact that recent developments in reimbursement for diagnosticimaging procedures may have on our customers. In the lastfew months alone, many new policies have been introduced,including the following.

• Multiple Imaging Procedure Payment DiscountOn January 1, The Centers for Medicare and MedicaidServices (CMS), the federal agency that administers theMedicare program, implemented a policy to discountpayments for certain imaging procedures performedby non-hospital outpatient providers.

• Coding Changes for 3-Dimensional Rendering ProceduresEffective January 1, the American Medical Association(AMA) revised the CPT codes for 3-D rendering procedures.Medicare and other payers have established new paymentrates for these codes and some restrictions apply.

• New Codes for Coronary CT ProceduresEffective January 1, 2006, the AMA introduced new CPTCategory III codes to report a number of coronary CTprocedures. Category III codes often require specificreporting requirements to be followed by providerssubmitting claims for these procedures.

As we look to 2007, we anticipate that a number of otherimportant changes may impact reimbursement for diagnosticimaging services. These include payment reductions for

Medicare Reimbursement Updateby Michael Becker, General Manager, Global Reimbursement, GE Healthcare

Reimbursement Information –Helps you understand and prepare for key developments affectingpayment for imaging services.

Contrast Agent and Radiopharmaceutical Reimbursement –Links you to GE Healthcare Medical Diagnostics customer support and documentation for coding and reimbursement related to the contrast agent and radiopharmaceutical products offered by the company.

Medicare Payment Rates –An on-line, interactive application that calculates Medicare paymentrates for selected imaging procedures for Hospital Outpatient orFreestanding Imaging Centers based on your geographic location.

Customer Advisories –Provides detailed information on coding, coverage and paymentamounts for specific imaging services like Cardiac CT and 3-Dimensional Rendering procedures. Also, there are Frequently Asked Questions type advisories to help you understand complex reimbursement policies like Stark Law and Medicare’s Multiple Imaging Procedure Discount.

Pro Formas –Helps you estimate the financial impact of purchasing some GE Healthcare imaging equipment and services. Customer ROI toolsfor some modalities like Magnetic Resonance and ComputedTomography are available through a GE Healthcare Sales Specialist or Representative.

Table 1.

Medicare payment rates available at: www.gehealthcare.com/reimbursement

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B E Y O N D T H E S C A N S Y S T E M L O N G E V I T Y

Addenbrooke’s Hospital, Cambridge, UK

In January 2006, the Cambridge University Hospitals NHSTrust, Addenbrooke’s Hospital reached the end of an era. Thelongest serving of the facility’s four GE 1.5T systems – theMRSO3 – was ramped down in preparation for de-installation.This system was originally installed on October 24, 1993 andfaithfully served the department and hospital with high-qualityimages since that time.

As a testament to the longevity and upgradeability of GE Healthcare’s MR systems, the system was upgraded four times during its 12 years of service life. Each upgradeenabled the system to continue providing state-of-the-artclinical applications and great image quality for the radiologistsat Addenbrooke’s.

The system started as a 4X system with the best imagingapplications available at that time. The system became a 5Xa few years later and subsequently was upgraded to an LX.Each upgrade brought significant patient benefits with fasterimaging speed and higher resolution, plus added phasedarray technology, faster reconstruction and improved coils.The LX upgrade brought the change from touch sensitiveplasma screen to an Octane host computer with a mouse-driven graphic interface. The ever expanding applicationsalso covered more modern scanning techniques such asbreast imaging.

In 2001, MRSO3 was one of the first systems to receive anupgrade to the EXCITE platform. This major upgrade wascarried out with the direct assistance of Milwaukee engineeringand proved a great success, ushering in the era of multi-channel imaging and parallel imaging, or ASSET™.

Although image quality was at an all time high, the freneticpace of change continued with the final metamorphosis to the HD platform in 2003. In this final incarnation, this MR system was the most technologically advanced, despitebeing by far the oldest system in use at the Addenbrooke’shospital. It remained in operation until the arrival in Januaryof the new GE Signa® HD 3.0T MR, purchased to replace this unit.

During its long life, MRSO3 with four upgrades was in operation for 4,293 days and, most important, imagedalmost 50,000 grateful patients.

About Addenbrooke’s Hospital

Addenbrooke’s, part of Cambridge University Hospitals NHSFoundation Trust, is a local teaching hospital for the University ofCambridge, a center for specialist services and a leader in researchand development. With approximately 1,100 beds, the facility employsover 6,500 staff dedicated to the provision of a wide range of clinical andnon-clinical services.

The Trust’s ‘2020 vision’ is a series of proposals designed to developAddenbrooke’s as a major center for treatment and research on aEuropean scale. The Trust is a leading international center for biomed-ical research and medical education, and shares its site with theUniversity of Cambridge, the Medical Research Council, the WellcomeTrust, the British Heart Foundation and Glaxo SmithKline.

The Hospital is a national and regional center for cancer services, livertransplants, organ transplantation, neurosciences and genetics; forexample 85 kidney transplants were performed in 2001.

A Tale of Two Upgrades

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B E Y O N D T H E S C A NS Y S T E M L O N G E V I T Y

Sharp hired Tom Fagan, an artist, to paint a mural on the center’s GE MR scanner, recently upgraded to a Signa HD system.

Sharp and Children’s MRI Center, San Diego, CA

In 1991, Sharp and Children’s MRI Center, part of Sharp MemorialHospital, installed a GE 1.5T long bore 4x MR scanner in thefacility to complement the center’s first MR scanner, which was purchased in 1986. “At that time, this GE MR scanner wasconsidered state-of-the-art,” said Russell Low, M.D., medicaldirector, who began his tenure at the facility at the same time following a fellowship in body imaging at StanfordMedical Center.

Dr. Low and the San Diego Diagnostic Radiology group havean extensive history of using GE’s MR technology. For thegroup, image quality and system reliability are importantconsiderations in any capital equipment purchase. What Dr. Low and his colleagues have also discovered is that theirchoice of a GE MR system has been a sound financial decision.

In 1999, the system underwent its first upgrade to an LXEcho Speed system. GE provides an upgrade path for all ofits MR systems, recognizing the fact that while MR technologyand applications advance over time, the system’s basicphysics and foundation remain relatively constant.

“There was no reason to remove and replace the entire system,”Dr. Low explained. While the magnet and all siting requirementsremained, the system was upgraded to provide improvementsin performance and image quality, including single shot fastspin echo (SSFSE), MR cholangiopancreatography (MRCP),and 3D gradient-echo MR angiography.

Although the crux of the decision to upgrade versus replacewas primarily a financial one, Dr. Low found the new capabilities on the LX model offered better images andfaster patient throughput, which together further increasedexam volume.

“It was a beautiful scanner, the best of the best, with excellenthomogenous images,” Dr. Low commented. While the scannercontinued to provide high-quality, diagnostic images, industrytrends and other factors, such as heightened demand andreferrals, continued to increase utilization of the GE MR system.

In September 2005, the system was again upgraded to the HD platform. “We were so pleased with the new upgradedSigna HD system that we decided to upgrade the room aswell, hiring an artist to paint murals on the wall and ultimately the scanner covers as well,” he said. “Our pediatric and adultpatients love the new artwork.

With what we’ve accomplished over 15 years with an MR system receiving two upgrades is impressive. Thelongevity of this MR system and its continuing productivityand excellent image quality is quite remarkable.”

Today, the bustling center conducts 1,800 MR exams eachmonth, triple its 1999 volume of 600 MR exams per month. “The large increase in volume speaks a lot to the quality, efficiency and economy of GE’s MR systems and to the everincreasing clinical value of MR imaging,” Dr. Low added. �

About Sharp Memorial Hospital

Sharp Memorial Hospital is the largest Sharp HealthCare hospital andis a designated trauma center for San Diego County. Located inKearny Mesa, it maintains 341 acute-care beds, including 35 beds forcritical care services. The hospital is especially known for outstandingprograms in cardiac and vascular care, cancer treatment, pulmonarycare services, rehabilitation, women’s health and multi-organ transplan-tation. Sharp Memorial also offers extensive outpatient services andprevention programs in support of Sharp’s overall emphasis on healthand wellness.

Fifty years after Sharp Memorial Hospital opened its doors, thehospital is breaking ground on an expansion to enhance San Diego’ssingle largest medical campus. The new hospital – scheduled forcompletion in 2007 – will be one of the most modern, technologicallyadvanced and patient-focused care centers in the nation.

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GE Healthcare

© 2006 General Electric Company GE Medical Systems, a General Electric Company doing business as GE Healthcare

Capture what youcouldn’t capture before.

PROPELLERStandard MR

Introducing Signa HDx technology from GE Healthcare. Parkinson’s disease patients. Poor vascularity in patients with diabetes. Women who need bilateral breast scanning in a single visit. Jittery kids. Once they were considered hard to scan patients. Now they’re simply patients. With high definition imaging and motion correction technology you can view all your patients exactly how you want. The same. MR Re-imagined.

To learn more visit www.gehealthcare.com/re-imagine

MR-0217-08.06-EN-US

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