2002 Magnetom Flash 3

Issue no. 3.2002

MAGNETOM F L A S H

1st MAGNETOM World Summit Nice, France July 10-12, 2002

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medical

MAGNETOM FLASH 3

ContentTopic 1. MAGNETOM WORLD SUMMIT NICE, FRANCE, JULY 10-12, 2002 Lectures July 11, 2002 ULTRA HIGH-FIELD A New Era with MAGNETOM Trio Comparison of Cardiac MRI at 3T and 1.5T: Preliminary Results MAGNETOM Allegra goes syngo Minimizing SAR for TSE-imaging with Hyperecho-TSE and TRAPS Cognitive Neuroscience Center at the Singapore General Hospital CARDIO VASCULAR Center of Excellence in Cardiovascular Imaging, Australia Cardiac Ambassadors Meeting, New York, June 27-29, 2002 Duke University Cardiac MR Center MR Angiography with Integrated Parallel Acquisition Techniques (iPAT) Contrast Enhanced MR Demonstration of Thoracic Central Veins Assessment of myocardial viability by Late Enhancement A New Dimension in Cardiac Viability Diagnosis WOMENS HEALTH Clinical MRI of the Breast for Lesion Detection PEDIATRIC IMAGING Fetal MRI: an Overview SPECTROSCOPY Interpretation of proton spectra of brain tumors using INTERPRET 68 66 62 46 50 52 54 56 58 60 28 30 34 38 44 Page 4 8 Topic ORTHOPEDICS MR Imaging of the Knee in Ironman Triathlon Athletes Magnetic Resonance Imaging of The Wrist MR imaging of non-displaced fracture of the humerus TECHNOLOGY CORNER Eight RF Receiver Channels and the Integrated Panoramic Array (IPA) Top Ten syngo Questions EVENTS Invitation from the Organizational committee to the MAGNETOM World WHOLE BODY MRI The era of whole body MRI MRI SAFETY Safety Considerations for Patients Referred for Cardiovascular MR Procedures OPEN CLASS MAGNETOM Concerto The economical open MR scanner New features of the MAGNETOM Concerto 97 99 92 86 84 78 82 Page

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The information presented in MAGNETOM Flash is for illustration only and is not intended to be relied upon by the reader for instruction as to the practice of medicine. Any health care practitioner reading this information is reminded that they must use their own learning, training and expertise in dealing with their individual patients. This material does not substitute for that duty and is not intended by Siemens Medical Solutions, Inc. to be used for any purpose in that regard.

Editorial Team

EditorialI wish MAGNETOM World team could meet more often in the glittering French resort of Nice. The Mediterranean sunshine, haute cuisine and fine wines provided the perfect ambiance for our speakers to really excel themselves and more than prove the genuine value of our MAGNETOM World community. This new format for serious talk and equally serious fun is something which has clearly fired the imaginations of everyone within our community. So its Au revoir to Nice and Bring it on, Miami, as we whet our appetites for more of the same in Florida in September, 2003. Please contact your local Siemens representative for more exciting details. Our MAGNETOM World working groups are busy. CMR Ambassadors met in New York and engaged in a very fruitful exchange of information with Siemens: we feel confident of seeing the impact of these exchanges in coming years with the development of new products from Siemens. The Pediatric MR Imaging workshop in Erlangen was also a success. It is clear that MR has a lot to offer in this area; developments and expectations in renal imaging and perfusion analysis were particularly interesting. Please take the time to enjoy our community web page, which is now online: www.SiemensMedical.com/MAGNETOM-World Here you will find case reports, images, clinical methods and clinical protocols, meeting information and training opportunities with MAGNETOM users. The protocol exchange on this web-page will run with Phoenix in the future, which will allow you to download image parameters from displayed images and use these parameters in your scanner. I really believe this to be the best way forward in protocol optimization. We are proud as a Siemens MR group to provide the forwardlooking solutions to our customers which leave our competitors struggling to keep up. Today they boast about providing 8 fast channels in MR scanners, even though this is something MAGNETOM systems had introduced in 1997, a full five years before. I believe the same thing is going to happen again: by around 2008 our competitors will have eventually come up with syngo-like solutions and Phoenix online protocol exchange opportunities and get excited about what, to us, is history. What can we do but smile sympathetically at the late-development of our competitors! I sincerely hope you all enjoy using the state of the art MAGNETOM scanners in a partnership which simply leads the field. Enjoy this issue of Flash.

Tony Enright, Ph.D. Asia Pacific Collaboration, Australia

Laurie Fisher, B.S.R.T., R, MR US Installed Base Manager, Malvern, PA

Marion Hellinger, MTRA MR MarketingApplication Training, Erlangen

Daniel Grosu, M.D. US R&D Collaborations, Malvern, PA

Milind Dhamankar, M.D. MR MarketingApplications, Erlangen

Michael Wendt, Ph.D. US R&D Collaborations, Malvern, PA

Dagmar ThomsikSchrpfer, Ph.D. MR Marketing-Products, Erlangen

Helmuth Schultze-Haakh, Ph.D. US R&D Collaborations, Malvern, PA

Peter Kreisler, Ph.D. Collaborations & Applications, Erlangen

Judy Behrens, R.T. (MR) (CT) Adv. Clinical Applications Specialist

Charlie Collins, B.S.R.T. Market Manager (USA), Erlangen

Raya Dubner Design Editor, Malvern, PA

A. Nejat Bengi, M.D. Editor in Chief

Antje Hellwich Design Editor, Erlangen

Achim Riedl Technical Support, Erlangen

We thank Harald Werner and Lawrence Tallentire for their editorial help.

MAGNETOM FLASH 3

1. MAGNETOM World Summit Nice, France, July 10-12, 2002

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MAGNETOM WORLD SUMMIT NICE

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www.SiemensMedical.com/MAGNETOM-World

MAGNETOM FLASH 3

Get Together July 10, 2002

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MAGNETOM FLASH 3

Lectures July 11, 2002Dr. Vivian S. Lee New York University, USADr. Lee then discussed living liver donors for transplantation: the right lobe from donors are transplanted to recipients. The livers have to be evaluated in detail for fatty infiltration, arterial anatomy, portal-hepatic veins and biliary ducts. The variants of biliary ducts are important to diagnose. Biliary anatomy using conventional 2D, single shot TSE techniques, is not easy to visualize. A technique developed by NYU - cholangiography with VIBE after Teslascan infusion** seems to offer an optimal solution. The VIBE sequence is applied 10-15 minutes following Teslascan administration. The isotropic images allow reconstruction in any plane which provides detailed anatomical information (Fig. 4). Moving from anatomy into function, Dr. Lee briefly mentioned renal studies in her clinic. Her renal examination protocol takes less than 30 minutes in total (Fig. 5, you can see the details of this protocol at www.SiemensMedical.com/MAGNETOM-World, under gastrointestinal imaging working group, clinical protocols). Gadolinium is, like inulin or creatinin, a useful marker for kidney function. This can be used for the diagnosis of renovascular disease, evaluating kidney transplant glomerular filtration rate and for split renal function. In renal transplant patients, MR can be used to understand the reason for dysfunction. In renovascular hypertension detection of stenosis is important, though evaluation of perfusion is very helpful in making the diagnosis in difficult cases. The addition of ACE inhibitors** like Captopril will also enhance the diagnostic information provided by MR. In renal artery stenosis, GFR (Glomerular filtration rate) should drop after the administration of ACE inhibitors. Dr. Lee also expressed her hopes for combining MR Angiography with GFR and renal function studies when these two applications are introduced into routine practice. Renal transplant donors have to be evaluated carefully. The renal arteries have to be normal and accessory renal arteries supplying the kidney have to be shown thoroughly clearly (Fig. 6). The arterial venous phase has to be seen (Fig. 7), as does the renal urogram (Fig. 8) showing the collecting system and ureters. Today, thanks to state of the art systems, functional information can also be provided with new sequences which scan 32 slices in three seconds, enabling 3D MR renography. The important question is whether tubular pathologies can be seen and differentiated from acute rejection. ATN (Acute Tubuler Necrosts): normal peak cortex & medulla, delayed renal pelvis peak enhancement. Acute rejection: all three peaks delayed. This evaluation requires visualization of cortex and medulla and being able to see their enhancement patterns. Automatic segmentation for kidneys differentiating the cortex, medulla and collecting system will be an important step in establishing MR, the modality of choice for applications like GFR quantification with MR, the visualization of enhancement patterns of cortex, medulla for diagnosis of ATN or rejection in renal transplant cases (Fig.9).

Dr. Lee started her talk by thanking Siemens for keeping the meeting short enough to allow MAGNETOM World members the time to enjoy the pleasures on offer in Nice (Fig. 1). The general theme of the talk was body MR imaging, moving from the subject of anatomy to that of function. VIBE (Volume interpolated breathhold examination) was the first topic. This technique allows 2D imaging in the abdomen to be replaced by 3D imaging, thanks to collaboration between Siemens scientists and NYU. VIBE is basically a Turbo MRA sequence with lower flip angle and intermittent fat suppression (Fig.2). As the images are isotropic, it allows multiprojection which helps diagnose lesions difficult to judge with axial examination, such as liver lesions at the dome of the liver. VIBE should be combined with proper timing schemes in order to see the arterial phase something which is very important using either a test bolus or care bolus for this timing. Vascular anatomy can also be seen in detail with this technique without extra contrast material. It is simply a case of retrieving the MIP or Volume rendered images from the clinical images created (Fig. 3). Dr. Lee also gave a couple of examples from her works using VIBE at NYU.

** Some of these non-Siemens devices described in the article may be pre-product prototypes that may not have completed US FDA, European CE Mark or other reviews for safety or effectiveness that are necessary prior to commercial distribution of these devices. Some devices may not be available in all countries where Siemens has systems. Siemens makes no claims as to the patient/staff safety, MR compatibility, or clinical capability of any of the non-Siemens devices included in the article. Before introduction of any device into the MR suite, the device should be inspected by qualified hospital personnel, and the non-magnetic properties of the device and its clinical operation in the magnetic field verified before it is used in a procedure. Use of these devices for animal or human procedures must comply with any applicable Governmental or local hospital safety and animal/ human studies committees requirements.

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Figure 1

Figure 2 3D VIBE TR/TE/flip: 4.2/1.8/12 1.5 - 2.5 mm thick slices 80 - 128 slices to cover liver (axial) Pixel size 1.6 x 2 x 2 mm Near isotropic pixel size MPR/MIP reconstructions Acquisition times < 25 sec Axial T1 GRE (BH) - Dual echo in-phase, opposed phase Coronal HASTE (BH) Pre-contrast 3D-GRE (BH) Timing examination Contrast-enhanced 3D-GRE: 20 ml - Arterial phase 30 min - Venous phase exam! (delay 45 60 sec) Repeat axial T1 GRE (in-phase) Figure 5 Renal MRI Protocol

Figure 3 Volume Rendered VIBE images

Figure 4 VIBE MR Cholangiography. Right lateral duct off left hepatic duct

Figure 6 Accesory renal arteries shown with renal MRA

Figure 9 Segmentation of the kidney

Figure 7 Visualization of renal veins in transplant donors

Figure 8 Later phases of renal MR examination show the collecting system and ureters 9


MAGNETOM FLASH 3

Dr. Thomas Lauenstein Essen University, Germany

Cerebrovascular MRIStroke is the third most common disease in the western world. Neuro protocols at Essen for screeening cerebrovascular diseases contain T1w SE, T2-w TSE, FLAIR, TOF and no i.v. contrast. The examination takes about 10 minutes. This examination allows to obtain of morphological information; detecting unknown pathologies and, to a certain degree, information can be provided regarding possible cerebrovascular diseases.

MR Colonography90 % of colon cancers develop from polyps. The detection and early removal of these polyps will stop the progression of disease. Transition time from a polyp to cancer is long between 5 and 10 years which makes this tool ideal for screening. The cancer risk depends on the size of the polyp. Essen University radiologists use a technique called Dark Lumen Imaging which involves the scanning of the whole colon after intrarectal administration of water and i.v. Gadolinium (Fig. 3). The scan starts after 75 seconds, which seems to be the optimal timing for the enhancement of polyps. MR screening detected many unknown lesions which affected treatment and follow-up of the screening population (Fig. 4).

Dr. Lauensteins topic was MRI based multi-organ screening. The question he asked at the beginning of his talk was Why MRI instead of other modalities? The answer he gave for the question was very convincing: there is no radiation involved, it is non-invasive, there are no known side effects of MR and, in his experience, its accuracy is greater than with other modalities due to improved contrast resolution and flexibility innate in MR.

Whole Body MR AngiographyWhole Body MRA (Fig. 1): Arterial disease is a systemic disease, which is why showing the whole arterial tree in patients with risk provides important information that might affect the lifestyle of patients. CP Body Array Coil and Angiosurf** provide excellent results in this examination (Fig. 2). Total acquisition time is 72 seconds. The entire examination time is 15 minutes.

Combining multiple exams in one protocolCertain cerebrovascular and cardiovascular diseases and cancers like colorectal cancer are treatable and have less consequences when diagnosed at an early stage. Essen University uses a 1.5 Tesla system, Sonata, and ultrafast sequences to do whole body screening. It also uses a system called Angiosurf** for moving patients in the MR scanner in such a way that wholebody scanning is made possible.

Cardiovascular diseaseThe Essen group uses TrueFISP cine, short axis and long axis imaging to evaluate the cardiac function. They also use TurboFLASH with a contrast agent*** to see the late enhancement which provides information about infarcted tissue, and which in some cases might reveal silent infarcts. The HASTE sequence is being used to evaluate the lung.

** Some of these non-Siemens devices described in the article may be pre-product prototypes that may not have completed US FDA, European CE Mark or other reviews for safety or effectiveness that are necessary prior to commercial distribution of these devices. Some devices may not be available in all countries where Siemens has systems. Siemens makes no claims as to the patient/staff safety, MR compatibility, or clinical capability of any of the non-Siemens devices included in the article. Before introduction of any device into the MR suite, the device should be inspected by qualified hospital personnel, and the non-magnetic properties of the device and its clinical operation in the magnetic field verified before it is used in a procedure. Use of these devices for animal or human procedures must comply with any applicable Governmental or local hospital safety and animal/ human studies committees requirements. *** This information concerns a use of contrast media that has not been approved by the Food and Drug Administration. (21 CFR 99.103 (a) (1) (i).

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Figure 1 Whole Body MRA covering from carotids to foot vessels

Figure 3 Dark Lumen MR Colonography and virtual colonoscopy

Figure 2 Visualization of distal vessels with array coils in whole body MRA

Figure 4 Visualization of sigmoid polyp with dark lumen MR Colonography and virtual colonoscopy

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MAGNETOM FLASH 3

Dr. Bart Op De Beeck Antwerp University, Belgium

Dr. Op De Beeck started his talk by mentioning the physical limits reached by MR systems today and the new solutions on offer for faster imaging techniques which include, of course, iPAT, the parallel imaging solution from Siemens with both mSENSE and GRAPPA techniques.

The physical principles of GRAPPA and mSENSE and hardware advantages with new coils especially 6 channel Body Array* were emphasized. The benefits of having both GRAPPA and mSENSE were summarized in this way: different applications need different algorithms for optimal solutions and Siemens was the only company which could provide this (see Flash 2/2002 for more details). The further advantage of autocalibration in decreasing examination times in comparison to separate pre-scan was also mentioned.

He summarized his view of iPAT imaging by answering a couple of important questions: s Is the image quality sufficient for clinical use? - Yes, especially for Flash and HASTE. s Which clinical applications are improved by employing PAT? - shorter breath hold abdominal studies with fewer artifacts; - increased temporal resolution in dynamic contrast studies; - greater coverage or higher spatial resolution in the same time, - fewer motion artifacts and reduced blurring

Figure 1 Better delineation of lesions and good corticomedullary differentiation with iPAT images. HASTE coronal images, high resolution iPAT image (Right), conventional (left) same acquisition time.

Figure 2 iPAT HASTE in diagnosis of multiple endocrine neoplasms

* The information about the 6 Channel Array Coil is being provided for planning purposes. The product is pending 510(k) review, and is not yet commercially available in the U.S.

Clinical implementation of parallel imaging is possible now using existing arrays and receiver systems. Particularly for applications with stringent requirements on imaging speed, parallel imaging can be a useful tool to enhance image quality, to improve imaging efficiency, and in general to overcome the acquisition speed limit in magnetic resonance imaging.

Figure 3 MR Cholangiography with iPAT in a patient with chronic pancreatitis

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Prof. Dr. Richard Semelka University of North Carolina, USA

Dr. Richard Semelkas talk offered an overall view of MR in the area of body imaging. He started his talk by stressing how straightforward protocols would help MR become standardized like CT. He stressed that a consistent good image quality will help consistent disease display. UNC protocols are divided into cooperative and noncooperative protocols. The future directions were defined as breathing independent sequences. Due to short bore MR systems and faster systems with advanced gradients, the number of non-cooperative patients has decreased. Most non-cooperative patients are said to be pediatric patients. FLASH, fat suppressed FLASH and out-of-phase FLASH are the sequences of choice for T1 weighted imaging. He expressed his happiness with 3D VIBE sequences that he received using the latest software (Fig. 1). The T2 weighted sequences he uses are basically HASTE and TurboSTIR (Fig. 2). Dr. Semelkas hopes for the new iPAT technique were summarized with the following words: I hope iPAT will take all good sequences and make image acquisition time shorter and make them essentially breathingindependent. HASTE is the best in all CT & MR approaches where there is the risk of metallic implants. A good example of this would be patients with hip replacement. According to Dr. Semelka, the most import sequence in MR is immediate post contrast FLASH or 3D VIBE. Dr. Semelka also touched on the topic of Contrast agents in MR and he offered the opinion that agents that combine early non-specific extracellular, and late hepatocyte selective properties will be the contrast medium of choice in the future.

Figure 1 3D VIBE image results

Figure 2 HASTE image showing intussusception

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MAGNETOM FLASH 3

Prof. Dr. Dudley Pennell Royal Brompton Hospital, London, UK

Dr. Pennells talk focused on the market for cardiac MR and the future directions it would take. He began by mentioning a depressing statistics saying: Half of deaths are caused by cardiovascular diseases, that is either you or the person sitting next to you. You can take your choice. He added that even though advanced medical care and preventive strategies were reducing the number of coronary disease cases per thousand population, in total the number of people with this ailment showed a tendency to increase due to the increased number of people reaching older ages.

Echocardiography was defined as the right choice for left ventricular function analysis: MR comes into play as soon as there is a myocardial infarction and there are changes in the shape of the heart. In this case, the choice could be 3D echo or well established MR. A series of cines are obtained from the base of the heart to the apex where the difference between end-systole and end-diastole is measured. From this data, ejection fraction and mass can be calculated (Fig. 1). An automized reliable technique was also speculated to have an impact on drug research. Turning then to specific diseases, Professor Pennell began by referring to hypertension. Left ventricular hypertrophy causes an increased risk of death in hypertensive patients. Measuring the mass of the myocardium in diagnosis of hypertrophy is a key step which can be done today with the available MR technology and software. Giving more statistical data, he said that 13,000,000 echos had been performed in the US last year. 10 % of echos do not contain sufficient information. This market can be captured by MR. Stress echo was also another procedure that could also be replaced by MR. Realtime MR is reliable method today which could be used when echo fails which is 15-20 % of the time (Fig. 2). TrueFISP was defined as the sequence of choice. Perfusion*** parametric maps created by MR generally match thallium abnormalities. Resolution with MR is 10 times better, subendocardial abnormality versus transmural perfusion abnormality can be differentiated by using MR (Fig.3a, Fig. 3b). The cases when MR perfusion can be used are: when SPECT fails, when there are attenuation artifacts with SPECT, where breast artifacts

in women occur and when there are attenuation artifacts in men. The timeline for clinical applicability of MR replacing SPECT seems to suggest this will happen in the very near future. Viability technique with MR received special attention during the talk. This technique in the case of 50 % or less enhancement of the myocardium shows an indication for surgery where one can assume that these areas will improve. Professor Pennells personal view was that this technique could be applied in 100% of all myocardial infarction cases (Fig. 4). Coronary anomalies was another area where cardiac MR could have an impact. Professor Pennell said that robust coronary imaging in clinical practice was not something that seemed possible in the near future, although the influence of 3 Tesla should not be ruled out. The obstacles facing Cardiac MR imaging lie with the fact that there is not enough experience out in the field and most centers are uncomfortable performing this examination. Professor Pennell finished his speech by saying that there is a huge potential in the market and that education is the most important issue in bringing cardiac MR into routine practice.

*** This information concerns a use of contrast media that has not been approved by the Food and Drug Administration. (21 CFR 99.103 (a) (1) (i).

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ED

ES

Aortic regurgitation LV LV LV LV LV End Diastole End Systole Stroke Volume Ejection fraction Mass 219 ml 107 ml 112 ml 51% 243 g 125 g/m2 103-161 28-72 49-113 47-75 96 +/-15

LV Mass index

Figure 1a

Figure 1b 3D Assessment of Ventricular Function

Rest

Stress

Figure 3a

Figure 2 Real-time: CMR vs Echo

Thallium Rest

Time to peak Peak intensity

Slope

Stress

Figure 3b Fig. 3a/3b: Myocardial Perfusion Parametric Maps

Figure 4 Viability technique showing transmural MI 15


MAGNETOM FLASH 3

Dr. Joerg Barkhausen Essen University, Germany

Dr. Barkhausen expressed his views regarding the future of vascular MRI. Standard examinations today cover a large spectrum of applications, including cerebral MRA, carotid MRA, thoracic aorta MRA, pulmonary artery MRA, imaging of the abdominal aorta and branches and applications under development such as peripheral MRA. Run-off vessels can be examined with dedicated array coils and Essen University has been performing whole body MR Angiography for screening purposes: this is a new application in the field of MR being developed by Essen University radiologists. The tendency he sees in overall MR Angiography is more in the direction of 4D imaging, i.e. anatomical imaging with temporal information added. Dr. Barkhausen also mentioned the different techniques in coronary angiography using navigators and breath-hold techniques. As a new idea being tried by centers throughout the world, he said that TrueFISP could also be used for MR Coronary Angiography. His overall summary of coronary angiography was that contrast enhanced MR angiography with breath-hold is a better technique than techniques requiring navigators and long examination times.

Dr. Barkhausen then talked about vascular wall imaging with dedicated coils and contrast material. Essen is in close collaboration with the Siemens MR Unit in developing new methods in vascular therapy with MR, and Dr. Barkhausen demonstrated the special catheters dedicated to MR vascular imaging as well as the real time image fusion technique that are being used by him in interventional vascular MR imaging. At the end of his talk, Dr. Barkhausen concluded that today MR is the diagnostic choice in almost all vascular diseases.

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MAGNETOM FLASH 3

Before chemotherapy

Prof. Dr. Albert van Rossum Free University Amsterdam, The Netherlands

Professor van Rossum gave a talk about the clinical indications of cardiac MR imaging, dividing the indications into two groups:

1. Primary Indications for Cardiac MRs Great vessel disease (aneurysm, dissection, coarctation) s Complex congenital heart disease (including RV function) s Pericardial disease (thickness, cysts, effusion) s Tumors s Cardiomyopathies (ARVD, HOCM) s Anomalous origin of coronary arteries / bypass graft patency s Myocardial viability (scar tissue)*** Figure 1 Pericardial Disease Monitoring tumor reduction (angiosarcoma) After chemotherapy

2. Secondary Indications (complementary to echo)s Global and regional LV function quantification: Volumes, mass, wall thickness, wall thickening s Valvular heart disease: Follow-up of volumes, quantification of regurgitation and shunts s Detection of ischemia (wall motion): Stress-induced wall motion abnormalities (dobutamine high dose), contractile reserve (dobutamine low dose)

*** This information concerns a use of contrast media that has not been approved by the Food and Drug Administration. (21 CFR 99.103 (a) (1) (i).

Figure 5 Hyperenhancement indicates non-viable myocardium. Subendocardial anterior infarct (arrows).

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Figure 3 Delayed contrast enhanced imaging. Single breath-hold image in diastole

Figure 4 Heart Failure excellent myocardial wall / blood pool definition, high resolution, easy and quick evaluation of the heart with TrueFISP.

Figure 2 Right ventricular tumor, metastasis of leiomyosarcoma. Comparison between echo and MR images

Figure 7 FDG PET versus CE MRI

Figure 6 Delayed CE MRI in patients with healed myocardial infarction. In enhancing areas there is focal interstitial fibrosis, where you can also observe regional dysfunction.

Figure 8 Quantification of aortic regurgitation. 19


MAGNETOM FLASH 3

Dr. Ozsarlak Antwerp University, Belgium

s Overall SNR is markedly improved and is on average 45-113 % superior to that obtained with a standard CP volume head coil. s The highest gains in SNR are observed in axial sequences. This presumably reflects the equal contributions of all coil elements. s On sagittal sequences, the gain in SNR is lower (in equal contributions of coil elements). Still, in the deeper parts of the brain (e.g. brainstem) SNR is better than with the CP Head Array Coil. s The high intrinsic SNR of the 8channel Head Array Coil can be used in conjunction with iPAT in order to: - decrease imaging time, - improve spatial resolution (multi-averaging), - or a combination of both.

Dr. Ozsarlaks talk summarized the wealth of experience in his clinic with Parallel Acquisition techniques and the neuro experiences with syngo MR 2002B Maestro Class Software.

Figure 1 Visualization of intracranial vessels after administration of 20 ml Gadolinium with 8-channel Head Array Coil. Conventional iPAT x2 TA= 220 TA= 120 iPAT x3 TA= 50

iPAT and CE AngiographyDr. Ozsarlak outlined the advantages gained by the 8-channel head coil and iPAT technique in image sharpness, image contrast and visualization of intracranial vessels. Background suppression was found to be same as with CP Head Array Coil. He also expressed his happiness with the water excitation technique which provided better background suppression than other techniques (Fig1, Fig2).

Spine Imaging and iPAT(Fig. 5, Fig. 6) Dr. Ozsarlak brought a new perspective to spine imaging with his observations that multi-averaging helped decrease artifacts in spine imaging, and provided better image quality than conventional approaches. Of course, in cases where there is need for extremely fast imaging, iPAT can be used to decrease imaging time. Overall, he was in support of GRAPPA technique as it created fewer artifacts in imaging the spine. Figure 5 TSE T2 Ac = 1, FOV = 300 x 300, Matrix = 307x512, SL = 4 mm, GRAPPA

MRI of the BrainThere were also remarkable advantages in imaging of the brain, according to Dr. Ozsarlak's evaluation (Fig. 3, Fig. 4): s The 8-channel Head Array coil provides excellent high-resolution imaging with anatomical coverage of the entire head. s The 8-channel Head Array coil is PAT optimized and allows the use of both SMASH (GRAPPA) and SENSE (mSENSE) type sequences.

STROKEThe results with color-coded maps in stroke imaging were important in evaluating stroke patients as a way of showing tissue at risk (Fig. 7).

Figure 7a 71-y-old male with acute stroke. Diffusion weighted images and ADC maps.

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Figure 2 8-channel Head Array Coil, TOF-we

Figure 3 Axial TSE T2-WI TR 3800 ms, TE 100 ms, recFOV with 512 matrix, TA 45.7 sec with PAT, normalization correction

Figure 4 Decreased distortion artifacts with iPAT. Left image result with 8 channel Head Array Coil and iPAT technique. Right with CP Head Array Coil.

Figure 6 iPAT cervical spine images with multi averaging (right) vs conventional technique(left). Conventional averages = 2 TA = 2 42 SL = 3 mm; FOV = 280 mm GRAPPA x2 averages = 4 TA = 3 30 SL = 3 mm; FOV = 280 mm swallowing every 20 sec!

Figure 7b 71-y-old male with acute stroke. Perfusion maps showing mean transit time (MTT)

Figure 7c 71-y-old male with acute stroke. Perfusion maps showing time to peak (TTP).

Figure 7d 71-y-old male with acute stroke. Perfusion maps showing relative cerebral blood volume (rel CBV)

Figure 7e 71-y-old male with acute stroke. Perfusion maps showing relative cerebral blood flow (rel CBF) 21


MAGNETOM FLASH 3

Evening Event July 11, 2002

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MAGNETOM FLASH 3

1.5 T July 2001

3T January 2002

Dr. Elna-Marie Larsson University Hospital Lund, Sweden

Dr. Larson talked about her experience in neuro MR imaging with 3 Tesla MAGNETOM Allegra system in a clinical setting. The advantages of a 3 Tesla system in general are increased SNR, increased susceptibility which is useful for fMRI and for visualization of iron-containing structures, and increase of chemical shift effect which is useful for MR spectroscopy. She expressed her satisfaction with improved image quality especially in MRA due to increased T1.SNR increase Increased susceptibility effect Increased SAR/power deposition Increase of chemical shift Longer T1 Increased contrast enhancement Increased flow artifacts + + + + + -

Figure 2 3T = Higher signal

Figure 3 3D CISS images with MAGNETOM Allegra

Figure 4 3D ToF without contrast injection

Figure 5 Higher SNR with MAGNETOM Allegra 3T. Acute stroke patient, 74-year old woman with right-sided hemiparesis.

Figure 1 3T compared with lower field strengths

T2 Turbo FLAIR

DWI

b = 1000 24

b = 4000


Dr. A. Gregory Sorensen Massachusetts General Hospital, USA

Dr. Sorensen's talk looked into the future of 3 Tesla and advanced neuro imaging with new diagnostic possibilities that can have an impact in the global burden of disease. In agreement with Dr. Larson, Dr. Sorensen also mentioned the basic advantages of 3 Tesla, including increased SNR and increased BOLD effect. He added that the fMRI community has largely migrated to 3 Tesla. Dr. Sorensen also talked about his experience with MAGNETOM Trio 8channel coils. Increased channels would be another factor helping improve applications that need more signal, such as diffusion tensor imaging and arterial spin labeling.

He also mentioned future applications, such as thalamic parcelation and MR tractography for the diagnosis of diseases with connections between different parts of the brain**. He added that super tensor imaging with hundreds of directions would help in the realization of these future applications. Computer Aided Diagnosis will play a major role in neuro imaging, was Dr. Sorensens considered view. He showed a couple of examples of his results with automatic segmentation of gray and white matter and also demonstrated the use of Auto Align technology which will help in the follow-up of patients at different times. This tool creates a 3D high resolution scout of the patient which registers the slices to be scanned and this allows the software to recognize the patient each time and places the slices in the exact same position in follow-up scans.

Figure 1 DTI can reveal anatomical structures that can not be seen by conventional MRI. The internal thalamic structure (12 different main nuclei) becomes visible in a DTI experiment due to local differences in anisotropic diffusion: All images courtesy of D.Tuch, MGH Boston

Figure 2 Image shows projections from rostral pons into the corona radiata via thalamus (blue fibers). Red fibers are the cerebellar pontine fibers projecting into the middle cerebellar peduncle. Data acquisition was done on a 3T MAGNETOM Allegra with 258 different diffusion gradient directions at a strength of 40mT/m, b-values 20000 s/mm2, TE = 140 ms, gradient pulse length 60 ms. Image courtesy of David Tuch, MGH Boston

** Some of these non-Siemens devices described in the article may be pre-product prototypes that may not have completed US FDA, European CE Mark or other reviews for safety or effectiveness that are necessary prior to commercial distribution of these devices. Some devices may not be available in all countries where Siemens has systems. Siemens makes no claims as to the patient/staff safety, MR compatibility, or clinical capability of any of the non-Siemens devices included in the article. Before introduction of any device into the MR suite, the device should be inspected by qualified hospital personnel, and the non-magnetic properties of the device and its clinical operation in the magnetic field verified before it is used in a procedure. Use of these devices for animal or human procedures must comply with any applicable Governmental or local hospital safety and animal/ human studies committees requirements.

Figure 3 Diffusion Tensor Imaging Color Display

Figure 4 CE carotid MR Angiography with 3 Tesla MAGNETOM Trio system 25


MAGNETOM FLASH 3

Super Technologists

MAGNETOM World includes a very important group called Super Technologists. Mr. Bart Schraa from Erasmus Medical Center, Rotterdam, spoke about an innovative use of Blueberry juice in MR Cholangiography.Blueberry juice serves to suppress the signal from the stomach and intestines in T2 weighted single shot images. This approach allows visualization of the biliary system without any signal superposing from the intestine or stomach. Mr. Mark Lourensz from St. Vincents Hospital, Melbourne talked about general abdominal imaging and provided valuable application tips.

The talks given by the Super Technologists enhanced the tremendous success of the MAGNETOM World Summit. After a splendid lunch, Dr. Civaia invited MAGNETOM World members to visit his clinic in Monaco where we were all able to admire the wonderful facilities at his disposal. The whole event was suitably rounded off with a champagne toast to this, and future MAGNETOM World Summits. The future looks great.

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Join us in helping to build excellence in Magnetic Resonance Imaging. s Hear from leading experts worldwide on best practices and clinical trends s Exchange ideas and your knowhow with other MAGNETOM users s Learn advanced techniques and innovative solutions s Enjoy the enticing tropical atmosphere unique to South Beach

We are proud to announce the 2nd MAGNETOM World Summit South Beach, Miami USA Autumn 2003

For more information please contact Raya Dubner from the MAGNETOM World organizational committee.

Email: Fax:

[email protected] +1 (732) 321-32 87

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A New Era with MAGNETOM TrioCcile Mohr, Ph.D. Ultra High-Field Segment Market Manager Siemens AG, Medical Solutions, MR Marketing, Erlangen The MAGNETOM Trio 3T Unlimited is attracting more and more users by setting new standards in 3T wholebody imaging. Hardly surprising, since the MAGNETOM Trio features: s SAR-reduction technology, including the hyperecho techniques, which ensure safe 3T patient examination and maximize anatomical coverage*. s Standard 8-fast RF channels, enabling the use of up to 32 LP (Linearly Polarized) coil elements s Diversity of iPAT-compatible local coils**, including 12 element Cervical-Thoracic-Lumbar spine array coil, 8-element neurovascular array coil, 8-element torso/pelvis coil, 8-element head array coil s syngo user interface featuring Inline Technology, reducing postprocessing to a minimum . s Duke University, Radiology Department, Durham, NC, USA s University of Freiburg, Germany s Max Planck Institute, Frankfurt, Germany s Hospital of University of Pennsylvania, Philadelphia, PA, USA s Oregon Health Sciences University, Portland, OR, USA s Georgetown University, Washington D.C., USA s Royal Holloway University of London, Egham, United Kingdom

The MAGNETOM Ultra High-Field community is now composed of 59 MAGNETOM Allegra and Trio sites all around the World, from Japan, Singapore, Turkey, Sweden, .. to the USA!

These are features which have enticed new members to join the MAGNETOM Trio network, and we at Siemens MR division are therefore proud to welcome and introduce: Figure 1 MAGNETOM Trio

* The information about this product is preliminary. The product is under development and is not commercially available in the U.S., and its future availability cannot be ensured. ** Some of these non-Siemens devices described in the article may be pre-product prototypes that may not have completed US FDA, European CE Mark or other reviews for safety or effectiveness that are necessary prior to commercial distribution of these devices. Some devices may not be available in all countries where Siemens has systems. Siemens makes no claims as to the patient/staff safety, MR compatibility, or clinical capability of any of the non-Siemens devices included in the article. Before introduction of any device into the MR suite, the device should be inspected by qualified hospital personnel, and the non-magnetic properties of the device and its clinical operation in the magnetic field verified before it is used in a procedure. Use of these devices for animal or human procedures must comply with any applicable Governmental or local hospital safety and animal/ human studies committees requirements.

Figure 2 iPAT at 3T of the lumbar spine TSE with 12-channel CTL spine array coil

TSE, GRAPPA TR 5500ms, TE 142ms FOV 300 mm x 300 mm, 512 Matrix, SL 4 mm Conventional TA: 3:28 min with PAT x2 TA: 1:50 min with PAT x3 TA: 1:17 min

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Figure 3 iPAT images of the abdomen with MAGNETOM Trio FLASH 2D with fatsat 8-channel abdominal array coil

FLASH 2D fatsat, GRAPPA FoV 300x 400, Matrix 256 Conventional, TA: 20 s with PAT factor 2, TA: 11s

Figure 4 3T images of the heart with iPAT cine TrueFISP, 8-channel cardiac array

Conventional TA 22 sec

with PAT factor 2 TA 12 sec

with PAT factor 3 TA 7 sec

Figure 5 Inline Technology on the new syngo user interface Automatic MIP calculations

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Comparison of Cardiac MRI at 3T and 1.5T: Preliminary ResultsDenise Hinton, Ph.D. Lawrence Wald, Ph.D. Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA John Pitts, R.T.R. (MR) John Kirsch, Ph.D. Franz Schmitt, Ph.D. Siemens Medical Solutions USA, Malvern, PA

IntroductionCardiovascular MRI is an application that places extreme demands on sensitivity, spatial resolution, and temporal resolution. As the number of ultra high-field (>1.5T) whole body systems is increasing, the need arises to evaluate the performance of these systems for non-neuro applications. The signal-to-noise advantages of higher magnetic field have been established for cardiac imaging [1]. However, issues of B0 homogeneity, RF tissue interaction [2], and the quality of the ECG signal can potentially reduce the gains offered by a higher magnetic field. We present here initial comparisons between 1.5T (MAGNETOM Sonata) and 3.0T (MAGNETOM Trio) whole body systems equipped with identical state of the art gradient sets (40 mT/m maximum, and 200 mT/m/s slew rate) and with similarly designed body coils. The goals of this study

were to compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios for matched studies conducted at both field strengths, and to evaluate the effects of higher SAR (Specific Absorption Rate) at 3 Tesla.

Results and Discussion1. Signal-to-Noise Ratio Comparison Figure 1 shows short axis bright blood cardiac images obtained on the same 74 year old male volunteer. The images compared are from slice planes located within 1 cm. The acquisition sequence is a breath-hold cine TrueFISP in which 19 images are obtained over the cardiac cycle with identical spatial resolution, TR, TE and 40 degree flip angle. The images were acquired with the body coil in transmit-receive mode and a phased array receiver coil at both field strengths [Fig. 1]. From a region of interest (ROI) analysis of these data

Figure 1 Short Axis cine TrueFISP images 74 year old healthy male volunteer. Breath-held and ECG triggered. Body coil transmit, phased array receiver coil Temporal Resolution = 19 phases over cardiac cycle TE = 1.6 ms, TR = 47 ms, Flip Angle = 40, FOV = 28 cm x 34 cm, Matrix 162 x 256, 5 mm slice thickness. Both SNR and CNR increase at 3.0T under identical imaging conditions.

1.5 TSystole

3.0 T

Diastole

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Figure 2 Quantitative Cardiac Evaluation at 3T (noise value taken from background), SNR increases in the myocardium of up to approximately 80%, and 50% increase in CNR between ventricular blood and myocardium, have been observed at 3T. We have measured with this study an SNR gain of up to a factor of 1.8 at 3T, which approaches the factor of 2 predicted for the SNR dependence on the magnet flux B0. Furthermore, in general, bright blood techniques at 3T have improved tissue-blood CNR compared to1.5T acquisitions under similar conditions. 2. Potential for 3T Cardiac Quantitative Evaluation The anterior and posterior thoracic components of a prototype 8 channel array coil (USA Instruments*) designed originally for head-neck angiography provided sufficient coverage of the cardiac anatomy. Cardiac images obtained using the array coil are shown in Figure 2. All major views, including short axis, four-chamber, and long axis are displayed in the panels of the Siemens quantitative cardiac evaluation software (Argus). The excellent image quality and high blood tissue CNR makes these data suitable for image processing to obtain quantitative measures of ventricular volume, myocardial mass, ejection fraction, etc. Cine TrueFISP images obtained on a 74-year-old male volunteer with known coronary artery disease. The two large panels display 4-chamber (left) and short axis (right) views. Long axis images are shown in the bottom panel.

* Some of these non-Siemens devices described in the article may be pre-product prototypes that may not have completed US FDA, European CE Mark or other reviews for safety or effectiveness that are necessary prior to commercial distribution of these devices. Some devices may not be available in all countries where Siemens has systems. Siemens makes no claims as to the patient/staff safety, MR compatibility, or clinical capability of any of the non-Siemens devices included in the article. Before introduction of any device into the MR suite, the device should be inspected by qualified hospital personnel, and the non-magnetic properties of the device and its clinical operation in the magnetic field verified before it is used in a procedure. Use of these devices for animal or human procedures must comply with any applicable Governmental or local hospital safety and animal/ human studies committees requirements.

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3T

1.5T

Particularly striking in these data compared to 1.5T is the improvement in anatomical detail (spatial resolution). For example, when the images of the 4-chamber view are displayed in cine mode, the motion of the chordae tendinae attached to the papillary muscle is well visualized. This is not readily observed at 1.5T.

3. SAR Issues Figure 3 displays a comparison of short axis cine images obtained on the volunteer shown in Figure 2 taken during systole (top panel) and end diastole (lower panel).

At 1.5T, flip angles typically above 50 degrees are needed (for the cine TrueFISP) to obtain high signal for the ventricular blood while minimizing in-flow artifacts and generating myocardial-blood pool CNR above 30. The concern at 3T for cardiac cine TrueFISP imaging is the SAR and achievable flip angle. SAR at 3T limits the flip angle to a maximum of 36 degrees for this subject (with pulse sequence parameters identical to those used at 1.5T), however, image quality and CNR are not significantly reduced. Modifications of RF pulse excitation profiles at 3T will be implemented that will reduce the SAR while allowing for higher flip angles, therefore generating cardiac images with higher overall SNR and CNR.

Figure 3 Short Axis cine True FISP images, both have CNR > 30. SAR limits 3T flip angle to less than 40 degrees, but image CNR remains comparable to 1.5T obtained with flip angle of 50 degrees.

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The feasibility of dark blood imaging at 3T is demonstrated in Figure 4. SAR issues are not encountered with this double-inversion prepared fast spin echo image obtained in one breathhold. Fat-suppressed images are shown on the right panel. The excellent resolution of the mitral (left atrioventricular) valve (circle) again demonstrates the SNR gain and high anatomical detail achievable at 3T.

ConclusionWe have demonstrated robust overall gains in SNR at 3T for cardiovascular MRI. Although SAR is an issue at 3T, CNR above 30 for ventricular blood and myocardium is achievable at 3T without any loss in cine temporal resolution. EKG gating and magnetic field homogeneity were not found to be major issues for these 3T studies. The whole body coil transmitter on the MAGNETOM Trio scanner has excellent homogeneity and efficiency, and no SAR issues were encountered with double IR, fat-suppressed, fast spin echo sequences. Phased array coils are critical for achieving maximal SNR gains. Fully equipped whole body 3T MRI scanners have excellent potential for meeting the demands for sensitivity and spatial resolution posed by cardiovascular imaging.

Figure 4 Dark blood fast spin echo images of 4-chamber view. Images on right with fat suppression; note resolution of left A-V valve.

References[ 1 ] Wen H, Dension TJ, Singerman RW, Balaban RS. The intrinsic signal-to-noise ratio in human cardiac imaging at 1.5, 3 and 4 T. J Magn Reson 1997; 125: 65-71. [ 2 ] Roeschmann P. Radiofrequency penetration and absorption in the human body: limitations to high-field whole-body nuclear magnetic resonance imaging. Med Phys 1986; 14: 922-931.

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MAGNETOM Allegra Goes syngoCcile Mohr, Ph.D. Ultra High-Field Segment Market Manager MR Division, Siemens AG Medical Solutions, Erlangen Germany

The MAGNETOM Allegra, the only 3T dedicated MR brain scanner, was upgraded to syngo MR in the clinical setting of the Neuroradiology Department of Lund University in Sweden. The 3T MR scanner now runs the latest syngo features, such as Inline Technology, and the Lund group is delighted with these Allegra upgrades. The population scanned on the machine with high-resolution morphological images is composed of patients with tumors, epilepsy, and vascular disease. The short bore of the Allegra magnet (1.25 m) also allows scanning of children from the age or 4-5 years without sedation or anesthesia.

Functional MRI using well-established motor, sensory and language tasks is used to map the brain before surgical removal of tumors. fMRI is then also used post-surgery to ensure that vital functions are not compromised by the surgical operation. The motor task consists of finger-tapping, the sensory task of stimulation of the palm of the patient with a brush or sponge. The sensory stimulation is facilitated by easy access to the patients hand due to the short bore of the magnet (only 1.25 m). The language tasks include silent word generation and silent rhyming. In addition, studies of perfusion and diffusion imaging in the brain are combined to assess stroke patients. MR-angiography studies, and especially Time-of-Flight, have excellent quality with improved visualization of small vessels, thanks to the 3T field strength of the MAGNETOM Allegra. MR spectroscopy will be used to assess possible metabolic alterations in patients with intracranial tumors and metabolic disease.

Figure 1 The Radiology Department of Lund University is a multidisciplinary group composed of physicists working closely with radiographers and radiologists. From left to right: Siemens Applications Specialist Gudrun Graf, Physicist Sara Brockstedt, Radiologist Elna Marie Larsson and Radiographer Titti Owman.

Figure 2 Scanning at the syngo MR console in Lund.

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Figure 3 The Radiology Department at the University of Lund, Sweden, host of the first MAGNETOM Allegra running under syngo.

Figure 4a Contrast Enhanced MRA of intracranial vessels. TR: 40 ms TE: 3.5 ms Flash 3D we. FOV: 200 x 200, Matrix: 269 x 512

Figure 4b Left 100 % SAR, right %28 SAR (TSE image with Hyperechoes)

Figure 4c CSI spectroscopy. Resolution 11x11x15 mm3, 6 averages, TE / TR = 20 / 1500 ms, k-space weighted sampling, acquisition time 9 min 21 sec

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The MAGNETOM UHF Community

Introduced in 1999, the MAGNETOM Allegra is the fastest 3T machine in the MR industry, featuring gradients with 40 mT/m maximum amplitude per axis (or 69 mT/m effective) and, more importantly, a slew rate of 400 mT/m/ms, equivalent to a rise time of 100 microsecond. This rise time allows fast imaging techniques in an unparalleled way, the key to techniques such as echo-planar imaging. In addition, the MAGNETOM Allegra has been made extremely compact (only 1.25 m long) to ease siting. For these reasons, the Allegra has been the choice of radiologists and basic science researchers, performing functional MRI and advanced brain MR techniques. More than 26 sites use the Allegra world-wide, including Japan and Turkey.

Europe 6 13

USA Continuing until December 2002, an ambitious world-wide upgrade program has been launched by Customer Service. All world-wide MAGNETOM Allegra will be upgraded to syngo. In addition, new options will soon be released, including the ability to image with integrated Parallel Acquisition Techniques (iPAT) SENSE and SMASH-based techniques for faster and better acquisitions. 18 13

Ralf Ladebeck, Project Manager MAGNETOM Allegra and Trio We are coordinating a world-wide team of highly technical skilled people. They will allow the transition from the older N3.5 software platform to syngo for all our MAGNETOM Allegra customers. We are excited to bring all the new syngo features to the customers, which will help them expand their applications as well as streamline their workflow. 36

MAGNETOM Allegra MAGNETOM Trio

ULTRA HIGH-FIELD

Japan 2 2

SE-Asia 1 2

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Minimizing SAR for TSE-imaging with Hyperecho*-TSE and TRAPSJuergen Hennig Ph.D. Matthias Weigel Ph.D. Klaus Scheffler Ph.D. Radiol. Klinik, University Freiburg, Germany As an example, let us consider a TSEsequence with 10 ms echo spacing (ESP), 2 ms pulse duration and 8 ms acquisition time. Reducing the rfpower of such a sequence by a factor of 2, by reducing the refocusing flip angles to ~125, will reduce the signal intensity to about 80-90 % of a fully refocused sequence, depending on the degree of sophistication for dealing with reduced flip angles. (Under Numaris 4 the (90+ /2)variant [2] is implemented, which yields about 90 %). The same SARreduction can be achieved by increasing the pulse duration to 4 ms. The concordant reduction in the acquisition time from 8 to 6 ms will lead to an increase in the bandwidth by a factor of 4/3 and therefore to a reduction in SNR to 86 %, which is roughly in the same range. Although this loss may not be appreciated, it certainly looks tolerable. The situation changes when the echo spacing is further reduced. At ESP = 6 ms with 3 ms acquisition time, prolongation of the pulse duration by 2 ms will shorten the acquisition time to 1 ms, leading to a loss in SNR by a factor of 3, which is clearly not tolerable. Therefore, for these high-duty applications, the flip angle reduction may be the only option. Even worse, very short echo spacings will pose even more severe SAR limits. Due to the increased number of pulses, a reduction by a factor of 2 may not be sufficient and the penalties in SNR will become increasingly severe. These problems have led to the situation that TSE, as one of the most desirable sequences for high field MR, has been somewhat less useful at 3 Tesla and more. Really nice images can be demonstrated, but these are often taken with reducedvolume coverage and/or at long echo spacings reminiscent of the early 90s, before the introduction of fast gradient systems.

Is Hyperecho the solution?This situation has quite significantly changed with the introduction of the hyperecho-mechanism last year [3]. By making use of symmetry relations in the spin behavior with respect to the signal evolution caused by rfpulses and gradients, it could be shown that the full 100 % spin echo signal can be recovered, even after a train of refocusing pulses with very low flip angle. The hyperecho mechanism is a generic new mechanism for signal formation, which can be used in numerous applications. Applied to TSE-imaging, it allows to reduce the rf-power by a factor of 2.5-4 and more without any loss in signal intensity by making use of the fact, that the overall signal-to-noise of images is determined by the signals around the center of k-space. Placing the hyperecho into the data encoding for the k-space center will thus lead to high SNR even though data at the edges of k-space may be somewhat reduced. Fig. 1 shows the flip angles and signal intensities of such a hyperecho TSE implementation. The initial gradual reduction of flip angles is necessary to avoid fluctuations of the echo amplitude, which would occur if constant flip angles were used [4] [5]. The total rf-power of this sequence is only 28 % of that of a fully refocused sequence. As shown in Fig.1b, the resulting signal intensity for brain parenchyma (T1 = 800 ms, T2 = 60 ms) at TE eff = 72 ms is even higher than that of a fullyrefocused sequence due to the contributions of stimulated echoes to the hyperecho. The resulting apparent reduction in the effective echo time can be used to further increase the echo train length at still moderate T2-contrast. Depending on the actual flip angles used, the T2-contrast of hyperecho images can be shown to

TSE (RARE,FSE...)-sequences are currently the most widely used MRtechniques for T2-weigthed diagnosis and an indispensable tool especially for examinations of various pathologies of the CNS [1]. The widespread use of these techniques is primarily due to the very robust and reliable T2-contrast based on the signal generation mechanism by spin echo refocusing.

3T ImagingIn the recent past, 3T-systems have been introduced not only for neuroscientific research with BOLD-based fMRI, but also with the specific purpose of routine clinical diagnosis. With the increasing susceptibility problems and inhomogeneity effects at higher fields, spin-echo refocusing seems to be particularly well suited for high field MR. Although such implementations have been successfully demonstrated even at 8T, the routine use of conventional TSE or HASTE at 3T and beyond is severely hampered by the high rf-power required by long echotrains with 180-refocusing pulses. In practice, this leads to severe limitations in the number of slices to be acquired at a given TR. A number of means have been introduced to deal with this problem. A flowchart of the various options is shown in diagram 1. The bottom line shows that no matter which option is chosen, some compromise has to be made in terms of SNR/acquisition time/volume coverage/image quality. 38

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180 160 140 120 100 80 60 40 20 Fig. 1a 0 0 20 40 60 80 100 te 120

Figure 1a Refocusing flip angles vs. echo time te along the echotrain of a hyperecho sequence with ETL=15, ESP = 8 ms, TEeff = 72 ms. Figure 1b calculated signal intensities for brain parenchyma (T1 = 800 ms, T2 = 60 ms) for the hyperecho sequence according to Fig. 1a (red) compared to a conventional TSE-sequence with 180 refocusing flip angles.

I (a.u.)

1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

Fig. 1b

0

0

20

40

60 TEeff

80

100

te 120

* The information about this product is preliminary. The product is under development and is not commercially available in the U.S., and its future availability cannot be ensured.

Figure 2 Hyperecho TSE images acquired with the parameters from Fig.1 at 1.5 T compared to conventional TSE (a). The excellent image quality of the hyperecho TSE-sequence (c) is demonstrated, whereas a reduction of the refocusing flip angle will lead to a severe signal loss (b).

TSE 180

TSE 60

HyperTSE 60

Figure 2a

Figure 2b

Figure 2c

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Figure 3 Conventional TSE-images (left) vs. hyperecho TSE images (right) acquired at 3T (MAGNETOM Trio): in plane resolution 0.4 x 0.4 mm2, slice thickness 2 mm, TE/TR = 109/5000 ms, ETL 27, matrix 512 x 512. With the longer echo train, SAR is even further reduced to 28 %.

180 160 140 120 100 80 60 40 20 Fig. 4a 0 0 50 100 150 200 te 250

Figure 4a Refocusing flip angles vs. echo time (te) along the echotrain of a TRAPS sequence with ETL = 27, ESP = 9 ms, TEeff = 72 ms. Figure 4b Calculated signal intensities for brain parenchyma (T1 = 800 ms, T2 = 60 ms) for this TRAPS sequence (red) compared to a conventional TSE-sequence with 180 refocusing flip angles.

I (a.u.)

1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

Fig. 4b

0

0

50

100

150

200

te 250

Figure 5 High resolution coronal TRAPS-TSE image acquired at 3T (MAGNETOM Trio). 40

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be equivalent to that in a conventional sequence at an echo time, which is shorter by 20-40 %. Figure 6 Multislice applications with Hyperecho. Sequence used is HASTE. Resulting images shown in Figs. 2 and 3 demonstrate the excellent image quality and show the dramatic improvement compared to a sequence with low flip angles.

TRAPSAs a somewhat complementary way to save rf power without any of the compromises of the conventional approaches, we have recently introduced the TRAPS-sequence (Transition between Pseudo-steady States) [6]. The physics of signal formation How to reduce SAR in TSE-sequences: Conventional approaches

1. increase TR decrease # of slices

2. increase the pulse duration

3. reduce refocusing flip angles

4. use simple pulses: Gauss, rectangular

increase the echo spacing

increase the acquisition bandwidth

reduced imaging efficiency (no breathhold T2) and/or bad volume coverage Diagram 1

at constant duration of the echotrain: reduced ETL, therefore longer acquisition time

at constant ETL: reduced image quality, less slices per TR

reduced SNR

poor slice definition, reduced SNR per mm SLTH, increased gap width

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in TRAPS is quite different from the hyperecho mechanism but the result, when applied to TSE, is very similar: rf power can be considerably reduced without any loss in signal intensity. TRAPS is based on the quite benign signal behavior of spins, once they have entered the so-called static pseudo-steady state (sPSS) [5]. After the sPSS has been reached, it can be shown that flip angles can be varied quite freely without any loss of coherence. Consequently the signal intensity can be driven back to 100 % by gradually increasing the refocusing flip angles to 180 for the signal encoding for the center of k-space. Fig. 4 shows flip angles and signal intensities for a rather simple implementation of TRAPS with linearly increasing flip angles to 180 and a subsequent linear decrease to the end of the echo train. Signal intensities again show the increase at TE eff compared to the fully refocused sequence. For this particular implementation the SAR was reduced to ~ 40 %. Fig. 5 shows a TRAPS-image acquired on a 3T system (MAGNETOM Trio) (ETL 27; 508 x 512 matrix; SLTH 2 mm; Flip 60; TE/TR = 109/6000 ms; FOV 19.1 x 24 cm) demonstrating the exceedingly good image quality achievable with this technique. For HASTE experiments, which use very long echotrains with short ESP, the reduction of SAR is especially important and relevant even at 1.5 T. Fig.6 demonstrates the improvement in imaging efficiency with a reduction of the required TR by a factor of

almost 4, which allows multislice applications with good volume coverage and sufficiently short acquisition times even to allow breath-hold imaging. Comparing TRAPS with hyperechoTSE [Fig. 1a vs. 4a], it is noted that the hyperecho mechanism allows a quite fast transition from low to high flip angles, whereas in TRAPS flip angle variations should in general stay with +/- 20 in subsequent refocusing periods. The signal variation in TRAPS is thus more gradual, but the SAR-savings are in general a little more modest compared to hyperechoes. This has been taken into account in the implementation of the sequence in the wip-package Hyperecho TSE. The decision on the best strategy is made by the program strategy, taking into consideration the relevant imaging parameters. The user can therefore continue to use TSE with considerably reduced SAR without having to worry about the intricacies of signal formation. A more flexible wip-package for expert users, where the relevant parameters are set through the Special Card of the Sequence menu, can also be made available.

References[ 1 ] Hennig J, Nauerth A, and Friedburg H: RARE imaging: a fast imaging method for clinical MR, Magnetic Resonance in Medicine 1986; 3:823-833 [ 2 ] Hennig J, Scheffler K, Easy Improvement of Signal-to-Noise in RARE sequences with Low Refocusing Flip Angles Magn Reson Med. 2000; 983-985. [ 3 ] Hennig J, Scheffler K, Hyperechoes, Magnet Reson Med 46(1):6-12 (2001) [ 4 ] Le Roux P, Hinks RS. Stabilization of echo amplitudes in FSE sequences. Magn Reson Med. 1993; 30:183-90. [ 5 ] Alsop DC. The sensitivity of low flip angle RARE imaging. Magn Reson Med. 1997; 37:176-84. [ 6 ] J. Hennig, T. Kluge, K. Scheffler. Multiecho Sequences with Variable Refocusing Flip Angles: Optimization of Signal Behavior Using Smooth Transitions between Pseudo Steady States (TRAPS). Proc. Xth ISMRM Honolulu, p.2365 (2002)

Take-home messageGiven the fact that progressing from 1.5 to 3 T is roughly equivalent to a 4-fold increase in rf-power, this leads to the following take-home message: Hyperecho-TSE allows one to perform TSE-imaging at high fields under similar conditions offered by the conventional sequence at 1.5 T. The full wealth of TSE-based imaging protocols is therefore available after suitable adaptation of the contrast to the changes in T1 and T2.

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KAPITEL

Siemens Ultra High-Field Programwww.SiemensMedical.comA91100-M-Z730-1-7600

The Siemens commitment to 3 Tesla can easily be seen in our leading product line in the Ultra High-Field segment. MAGNETOM Allegra See the Mind. Dedicated to brain imaging, this most compact 3T scanner is equipped with the strongest gradients in the market. MAGNETOM Trio See the Body. The Trio is your system for whole body applications in the 3T Ultra High-Field sector. It offers a full 40 cm Field of View and is the shortest 3T scanner allowing clinical whole-body imaging at 3 Tesla. Siemens Medical Solutions that help

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Cognitive Neuroscience Center at the Singapore General HospitalCcile Mohr, Ph.D. Ultra High-Field Segment Market Manager MR Division, Siemens AG Medical Solutions, Erlangen Germany

Principal Investigator: Dr. Michael Chee M.D

What we doThe Cognitive Neuroscience Laboratory uses functional magnetic resonance imaging (fMRI) to study the organization of the bilingual brain. We seek to uncover the neural correlates to understand why some persons are more adept at learning a second language than others. fMRI harnesses the fact that regional increases in blood flow occur in a task-dependent manner. For instance, thinking about words activates parts of the brain that are involved in language processing, whereas the passive viewing of a flashing checkerboard activates visual areas. This change or modulation in regional blood flow is detectable by magnetic resonance imaging: however, since the signal change is small and the background noise is relatively high, careful design of experiments and thoughtful data analysis are required to draw meaningful inferences about how the brain works. The team carrying out this research comes from varied backgrounds. The principal investigator is a neurologist with special training in clinical neurophysiology and an interest in cognitive neuroscience. Also on board are graduates in computer science and psychology. The lab collaborates with physicists from Duke University and 44

Figure 1 Delivery of the MAGNETOM Allegra to the Cognitive Neuroscience Center at the Singapore General Hospital

Figure 2 Dr. Michael Chee, Neurologist and Principal Investigator of the Cognitive Neuroscience Laboratory, Singapore General Hospital, in front of his MAGNETOM 3T Allegra. Dr. Chee's interest is in studying why individuals differ in their capability for second language acquisition. The increased sensitivity for functional MRI studies offered by 3 Tesla MR scanners, as well as the scanning speed needed for such studies, are excellent reasons why Dr. Chee has decided to acquire a MAGNETOM Allegra the 3T MR scanner with the fastest gradients in the industry (40 mT/m per axis or 69 mT/m effective and a slew rate of 400 mT/m/ms). Apart from purely technical considerations, the choice of the Allegra was also due to my confidence in Siemens post sales technical service, a factor investigators ignore at their peril, says Dr. Chee.

Figure 3 Research team Back row: Steve Graham Ph.D. Experimental Psychology (memory), Chun Siong Soon BSc BA, Physics and Philosophy (language), Chris Westphal BSc Psychology (memory), Vinod Venkatraman MSc Computer Science (methods development) Joshua Goh BA Hons (memory) Front row: Hwee Ling Lee BA (language), Mike Chee M.D (prinicipal investigator)

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the University of Freiburg, a neurologist at Massachusetts General Hospital, Boston and with psychologists from the National University of Singapore and the National Institutes of Education.

Figure 4 Glowing beauty. No, this is not the latest MAGNETOM Allegra design! This visual effect is caused by the projector located behind the magnet. The projector is used for presentation of visual stimulation to patients and subjects undergoing a functional MRI examination at the Cognitive Neuroscience Laboratory.

BackgroundA matter of increasing importance in an increasingly globalized world is how to deal best with the challenge of communicating in multiple languages. The need to acquire one language (English) as the language of business, technology and international communication competes with personal, cultural and political needs to preserve some sense of distinctiveness within a particular group of people. Questions previously of interest to scholars have only now become important to policy makers: Does the concept of critical periods of development apply to second language learning? How flexible is the brain in terms of its organization with respect to language? What kind of changes occur in the brain when one learns a second language? Are there any predictors for proficiency or is the attainment of proficiency merely a function of practice? Whereas previous knowledge on functional anatomical relationships has been dependent on the occurrence of brain lesions or epilepsy, functional MRI affords the study of language processing in healthy volunteers without exposure to ionising radiation.

and older studies that suggested separate areas for different languages is that previous studies did not take into account proficiency differences. We found that these may modulate activation on account of the greater cognitive effort required to process words in ones less proficient language. Arising from this, we also found that word frequency reliably modulates brain activation providing a means of indexing exposure-dependent modulation of brain activation. We propose using this device to track brain activation changes during the course of language acquisition. We are concurrently working on the neural correlates of how phonological skills relate to language acquisition capacity.

Representative Publications:[ 1 ] Chee MW, Buckner RL, Savoy RL. Right hemisphere language in a neurologically normal dextral: a fMRI study. Neuroreport 1998; 9(15): 3499-3502 [ 2 ] Chee MW, Buckner RL, OCraven KM , Bergida R, Rosen BR, Savoy RL. Auditory and Visual Word Processing Studied with fMRI. Hum Brain Map 1999; 7(1): 15-28 [ 3 ] Chee MWL, Tan EWL, Thiel T. Mandarin and English single word processing studied with fMRI. J Neuroscience 1999 19:3050-3056. [ 4 ] Chee MWL, Caplan D, Soon CS, Sriram N, Tan EWL, Thiel T. Weekes. B. Processing of visually presented sentences in Mandarin and English studied with fMRI. Neuron 1999, 23:127-137. [ 5 ] Chee MWL, Weekes B, Lee KM, Soon CS, Schrieber A, Hoon JJ, Chee M. Overlap and Dissociation of Semantic Processing of Chinese Characters, English Words and Pictures: Evidence from fMRI. Neuroimage 2000; 12: 392-403. [ 6 ] Chee MWL, Sriram N, Soon CS, Lee KM. Dorsolateral prefrontal cortex and the implicit association of concepts and attributes. Neuroreport 2000; 11: 135-140. [ 7 ] Chee MWL, Hon N, Lee HL, Soon CS. Relative language proficiency modulates BOLD signal change when bilinguals perform semantic judgements. Neuroimage 2001; 13:1155-63. [ 8 ] Chee MWL, Hon N, Caplan D, Lee HL, Goh J. Frequency of concrete words modulates prefrontal activation during semantic judgments. Neuroimage 2002:16:259-268 45

Where do we see ourselves in two to five years?Our work will continue to relate to human cognition and involve language and memory in particular, but we expect to shift into more clinically related areas in work relating to human memory. In the language domain, we will work with other laboratories to determine the functional-anatomical correlates of individuals with differing capacity to acquire a second language. In the memory domain, we hope to study the functional-anatomical correlates of human memory under conditions of sleep deprivation and aging and to evaluate the effects of intervention, whether pharmacological or behavioral, on these.

What we have discoveredWe have shown that in fluent bilinguals, similar brain regions are activated during single word and sentence level processing in two dramatically different languages: English and Mandarin. We have also established that processing of Chinese characters for meaning does not differ significantly from the processing of English words for meaning and that these differ from the processing of pictures for meaning. One explanation for differences between recent studies on the bilingual brain


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Center of Excellence in Cardiovascular Imaging, AustraliaTony Enright, Ph.D. Asia Pacific Collaboration, Australia

SummaryThe MIA (Medical Imaging Australasia) Group has identified noninvasive cardiovascular imaging with magnetic resonance imaging (MRI) and multi-detector computerised tomography (MDCT) as the future of cardiovascular imaging. Siemens shares this vision with their latest cardiovascular technologies in MRI and multi-slice detector CT, Siemens MAGNETOM Sonata MRI scanner and SOMATOM Sensation 16 CT. There is presently no other center in Australia with this combination of technology working side-by-side for the diagnosis of cardiac diseases. It is a unique opportunity to evaluate within Australia the clinical roles of these new technologies in the provision of cardiovascular care services and patient wellness. Key to the success of this vision is the collaboration between the Radiology and Cardiology fraternities in order to unite the expertise and know-how of Radiology with the experience of Cardiologists in the fields of myocardial and coronary imaging. This is Adelaide Cardiac Imaging (ACI), a collaborative venture between a Cardiology and Radiology group for the purposes of providing clinical excellence in the cutting-edge fields of cardiovascular imaging with MRI and MDCT. This collaboration encompasses the sharing of financial, administrative and technical aspects of the program.

Figure 1 Adelaide Cardiac Imaging Team. Left to right : Radiologist Dr. Shaun Fowler, Cardiologist Dr. Daniel Cehic, Cardiologist Dr. Stephen Worthley, Radiologist Dr. Charles Lott, Cardiologist Dr. Michael Brown With the formation of ACI, there is a substantive investment made into the clinical research of cutting-edge diagnostic protocols for cardiovascular care, which have only recently become available with state-of-theart techniques, such as coronary MR angiography and plaque imaging. Employing new Siemens MRI and CT scanners, the center will combine clinical excellence with research. Siemens supports this initiative through a close collaboration with Siemens Global Development groups and its Cardiovascular Research and Development facility, located at Northwestern University in Chicago. Together with the clinical skill sets involved in ACI, this center has the credentials for growth to a world class center of excellence in cardiovascular imaging.

Why the focus on cardiovascular diseases?In the Western World cardiovascular disease is the single leading cause of mortality. Rapidly developing magnetic resonance imaging (MRI) and computed tomography (CT) scanners are allowing clinicians to develop new methods for treating complex cardiovascular problems and researching cardiovascular disease.

Clinical Skill Sets for Excellence in Cardiac ImagingFrom a clinical perspective it is the skill sets, brought together in a close collaboration of cardiology and diagnostic imaging, that point the way to success in this challenging field. Dr. Stephen Worthley, an interventional cardiologist who has completed a Ph.D. thesis in MRI and coronary atherosclerosis at the Mount Sinai Medical Center in New York, continues his successful career in clinical

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Figure 2 Dedicated task card with syngo including automatic cine display, postage stamp reference images, ecg graphics and triggering setup.

Figure 3 Argus cardiac post processing software with functionalities like ventricular function assessment, quantitative flow assessment, multipanel cine review, avi movie maker.

day running of the cardiovascular imaging program with MRI and MDCT a collaboration that is Adelaide Cardiac Imaging. and academic cardiology with the ACI program. In the last 5 years alone, Dr. Worthley has published more than 80 manuscripts and abstracts in the fields of cardiovascular imaging and intervention, and authored book chapters on Cardiovascular MRI, including for the prestigious cardiac text, Hursts The Heart. He holds a number of grants for research into the utility of MRI and intravascular ultrasound for imaging atherosclerosis, including projects that are ongoing in both Melbourne and Adelaide in Australia. Dr. Worthley joins the Adelaide Cardiology group (Fig. 1) together with a dedicated group of Radiologists (Dr. Shaun Fowler and Dr. Charles Lott) and Cardiologists (Dr. Michael Brown and Dr. Daniel Cehic) who together are involved in the day-toIn addition to a world-wide team of experts, the ACI program can only be supported by imaging technology and especially by MRI scanners able to be operated by cardiologists, placing cardiology at the forefront of the examination of one of the most challenging organs the heart. In this respect, the MAGNETOM Sonatas Maestro user interface (Fig. 2) is designed with unique features targeting the needs of cardiology. 47


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With this scanner we expect traditional interactions between radiology and cardiology to change, placing radiologists together with cardiologists like Dr. Worthley, operating the console guiding and planning the patients examination. This direct involvement of cardiologists is a crucial point to ensure success in validating new cardiac imaging techniques.

New Clinical Services Offered to Patients in AustraliaACI is the first center in Australia to offer state-of-the-art non-invasive cardiac imaging to the people of South Australia. Along with a comprehensive suite of cardiovascular services, ACI offers new care services, such as Chest Pain Investigation: referrals for non-invasive coronary angiography can undergo noninvasive tests on MRI or 16-slice multi-detector CT. An extensive program for Cardiovascular Risk Assessment also offers: a. Conventional Risk Factor Review b. Cardiovascular MRI: non-invasive evaluation of heart function (Fig. 3) and direct imaging of atherosclerosis c. Coronary Calcium Scoring: noninvasive calculation of calcification in the coronary arteries, a predictor of risk for future heart attacks d. Physician Review

Figure 4 Cardiac imaging with GRAPPA technique. Imaging parameters: GRAPPA x 2, TR 35 msec, 7 second breath-hold 298 x 256 pixels, 262 mm x 300 mm FOV, 0.88 mm x 1.17 mm x 7 mm voxels

other center in Australia with the SMASH-based technology GRAPPA, introduced on the MAGNETOM Sonata to address the limitations in SENSE technologies for cardiovascular imaging applications. The GRAPPA technique helps reduce breath-hold duration, therefore making the examination even more comfortable for patients. In addition, the GRAPPA technique ensures the best image quality thanks to a unique technology called Auto-Calibration. (Fig. 4)

Cardiovascular examinations with the MAGNETOM Sonata avoids patient exposure to radiation by using magnetic resonance imaging. SOMATOM Sensation-16 minimises radiation exposure by employing optimised scan protocols and dose modulation technology. ACI have the expertise to decide which is the best diagnostic technique for their patients.

The new 16-slice CT technology introduced with SOMATOM Sensation-16 now brings into view new diagnostic information in imaging coronary artery disease and cardiac function. The SOMATOM Sensation 16 is the ultimate multi-slice CT solution offering virtually unlimited isotropic volume acquisition with 16 simultaneously acquired slices, without compromising clinical applications. ACI will be the first recipient of the Sensation-16 in the whole of Australia. Both scanners operate on a multimodality user interface Siemens syngo allowing clinical personnel to cross-train on all imaging modalities. syngo creates new ways of looking at image data and integrates MRI and CT data together for a comprehensive diagnosis. This is the first center of its kind in Australia and one of only a few hospitals world-wide to boast such a combination of MAGNETOM Sonata and SOMATOM Sensation-16, combining high performance in MR and CT for cardiac diagnosis and care.

More on the TechnologyThe technologies underpinning this venture include an MRI scanner designed to support the demanding requirements of advanced MR imaging applications, such as cardiovascular examinations. MAGNETOM Sonata features the highest level of speed available in the industry. ACI is the first center in Australia to evaluate in clinical practice side-by-side both parallel imaging technologies SENSE and SMASH new imaging techniques which speed up the examination times. There is currently no

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A Collaboration to Foster Further InnovationsSiemens has invested heavily in the support of research and advanced clinical applications worldwide, especially in cutting-edge projects such as the one in ACI. This is a deliberate strategy by Siemens to maintain its place at the top of the technology pyramid and, as such, is becoming increasingly the partner of choice for customers such as ACI, operating advanced applications. MRI offers rapidly advancing and improving technologies which we can pass on to our key collaboration partners, since this growth is sustained only by close collaboration with groups who have the necessary skill sets and who are willing to work at the forefront of these applications and their clinical evaluation. ACI have made a major investment into cardiovascular research, and validation of emerging technologies. ACI is therefore a strong partner for this collaboration, with a commitment to clinical excellence and education. Siemens supports this venture with close cooperation with Siemens Global Development groups in Europe and the US, as well as Siemens Cardiac Research and Development facility located at Northwestern University in Chicago. This collaboration is facilitated by several Siemens physicists and engineers. To ensure that the entry level of this technology sets the standard for Australia, there is provision for the training of clinical staff at established centers of excellence overseas. This is backed up by the local and direct support of an Asian-Australian Applications Scientist, as well as priority Applications Support from Siemens trained Applications Team.

Figure 5 Cardiac Ambassadors at New York meeting Adelaide Cardiac Imaging will participate in Siemens Cardiac Ambassadors Club Meetings, the latest held in New York in June. There, ACI group was able to share its experience with international clinical experts, as well as with Siemens Medical scientists. Siemens Cardiac Ambassador Club is the ultimate users club providing interactions with a high-level peer network of key global clinical researchers in cardiac, and the chance to participate in steering Siemens future technology growth in this area. (Fig. 5)

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Cardiac Ambassadors Meeting, New York, June 27-29, 2002

Figure 1 Cardiac Ambassadors Daisy Chien Ph.D. Siemens AG The Cardiac Ambassadors Meeting held in New York this summer proved to be a great success. More than 100 people attended, including 85 users from 15 countries (Fig. 1). Close to 20 colleagues from Siemens Erlangen, Siemens Iselin, and Siemens Corporate Research Princeton were present to support the meeting. Local Siemens offices sent out the invitations to a representative from each cardiovascular MR reference site, which received an enthusiastic response from many sites worldwide. In addition to the discussion forum, there was a hands-on demonstration session in which new software (syngo 2002B) and postprocessing tools were shown. There were also demonstrations of the new Argus and Vessel View software. Dr. Brett Cowan, from Auckland, New Zealand, showed his 3D modeling software, which generated much interest among the audience. A number of centers prepared posters highlighting their centers and their work. Furthermore, many participants prepared interesting cases to share with each other. During one of the demonstration sessions, Dr. Charles Cheng (HealthTech International, Taiwan), Dr. Vicente Martinez (ERESA Imaging Center, Spain) and Dr. Corinna Cozeb Poetica (Klinikum Krefeld, Germany) highlighted and discussed interesting cases. Dr. Barkhausen, Dr. Heiko Mahrholdt, and Dr. Anja Wagner were also available to give an analysis of their clinical results. After much intensive work together, the participants went out on the town for an enjoyable evening in which a fine dinner was followed by tickets to the glamorous Broadway show 'Aida'.

Second DayThe second day consisted of summaries of the focus sessions given by Siemens users. This provided all participants with an excellent overview, as they had not been able to attend selected focus sessions that ran in parallel with other sessions. The Siemens presentations highlighted new features in the product, as well as new techniques and innovations, to inform participants of new and important developments. It was a very fruitful exchange for everyone present. The response from the participants was very positive and the questionnaire results more than confirmed the importance and effectiveness of the meeting. The scores are set out below. An important aspect of this meeting was the opportunity for an open forum for interaction among users worldwide. Many participants appreciated the chance to meet and get to know colleagues who are active in cardiovascular MR.

First DayAfter a welcome dinner and gettogether, the first working day consisted of parallel focus sessions on a number of topics. The special focus ses

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2002 Magnetom Flash 3