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GE Healthcare pulse S I G N A THE MAGAZINE OF MR • AUTUMN 2007 The IDEAL Approach to Separating Water and Fat page 16 2D Versus 3D page 14 Re-Defining the Next Generation of High Definition page 32 Making the Decision to Add MRI page 48 imagination at work The information contained in this document is current as of publication of the magazine. TA B L E O F CONTENTS GE News: The IDEAL Solution for Fat and Water Separation Page 6 Clinical Value: One Breath Away from Volumetric In-Phase, Opposed-Phase Fat/Water Imaging Page 24 Technical Innovation: Enhancements Bring Sophisticated MR Applications Within the Reach of Everyone Page 40 GE Healthcare News Clinical Value Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Volumetric Imaging Magnetizes Radiology . . . . . . . . . . . . . . . . 12 New Volume Acquisition Helps Clinicians Detect Small Lesions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 The Clinical Proof of 2D Versus 3D . . . . . . . . . . . . . . . . . . . . . . . . 14 The IDEAL Solution for Fat and Water Separation. . . . . . . . . . . 6 Introducing the Next Generation of HD MR . . . . . . . . . . . . . . . . . 7 Calendar of Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 GE Opens China’s First MR Application Academy . . . . . . . . . . . 9 3.0T Continues to Bring Users Together . . . . . . . . . . . . . . . . . . . 10 Consistent, Reliable, Fat-Suppressed Imaging Even with Difficult Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 High-Resolution, Isotropic-Voxel Acquisition Technique Improves Quality and Utility of Diffusion-Weighted and Diffusion Tensor Imaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 One Breath Away from Volumetric In-Phase, Opposed-Phase Fat/Water Imaging . . . . . . . . . . . . . . . . . . . . . . 24 Efficient Image Quality Enhancements in Temporal Bone Imaging Using PROPELLER HD. . . . . . . . . . 28 Validation of an Automated Left Ventricular Segmentation Technique for Quantifying Stroke Volume. . . 30 Publications Team: GE Contributors: David Handler General Manager, MR Global Marketing Chris Fitzpatrick MR Global Marketing Programs Manager Renée Adelle Stasiewicz Global Marketing Communications Manager, Diagnostic Imaging Modalities Joanna Jobson MR Global Marketing Programs Manager Katherine Patterson Global Marketing Communications Manager, MR Maria Piazza MR Global Marketing Programs Manager Mary Beth Massat Editorial Consultant © 2007 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. 2 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. Beyond the Scan: Medicare Reimbursement Update Page 52 Technical Innovations Re-Defining the Next Generation of High Definition. . . . . . . . 32 3D FSE Reduces Scan Time, Generates Thinner Slices . . . . . 34 New Parallel Imaging Method Enhances Imaging Speed and Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Quantitative Tool for Neurological Brain Evaluation . . . . . . . 39 Enhancements Bring Sophisticated MR Applications Within the Reach of Everyone . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Robust NCE Techniques Remain a Viable Alternative for MR Angiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Beyond the Scan Advanced fMRI Techniques Provide Valuable Information, Change Course of Treatment for Neurosurgical Patients. . . 44 The Right Choice for Your Community: Making the Decision to Add MRI . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Medicare Reimbursement Update . . . . . . . . . . . . . . . . . . . . . . . . 52 Signa 3.0T Users Share Best Practices, Clinical Techniques with Users Around the World . . . . . . . . . . . . . . . . . 53 The information contained in this document is current as of publication of the magazine. G E H E A LT H C A R E N E W S WELCOME Welcome Ever stop and think about the incredible strides medical research has made in the last 100 years? I admit it, working in this industry can make us harder to impress than the average person. But think about it. In the last 100 years, we’ve seen the discovery of the cause of rickets (1916) to the discovery of penicillin (1940s). It was only in the last 50 years or so when they found that smoking is a leading cause of cancer (1956) or that chemotherapy could be used as a treatment for cancer (1970s). Of course, we couldn’t forget Sir Peter Mansfield and his studies that led to the development of the MRI in 1973. Incredible stories. But they underscore the point that the scientific advancements in healthcare are really just starting to gain momentum. There’s so much ahead of us – every day brings another finding or advancement – and every day lives are saved that previously would not have been. What an exciting time to be in healthcare! 4 A GE Healthcare MR publication • Autumn 2007 But even the most advanced imaging tools won’t succeed in today’s clinical environment if they aren’t delivering what radiologists need. They must be clear, accurate and specific. Otherwise, our mission will fail to deliver what it ultimately needs to do: giving radiologists the tools they need to do their job to save lives. No small task. In his 2007 book, How Doctors Think, Dr. Jerome Groopman discusses a study from Dr. E. James Potchen that indicates radiologists need to be able to gather the information they need from images in 38 seconds. Thirty-eight seconds! What this means to us is that our images need to clearly, consistently and accurately deliver in a very short period of time. Something we take to heart. This is why we at GE Healthcare are pleased to introduce to you the next dimension in HD MR imaging – the Signa® HDxt. These new acquisitions are truly exciting – and are in step with our vision to give you what you need: images that are clear, concise and consistent. Every time. For every The information contained in this document is current as of publication of the magazine. W E L C O M E G E H E A LT H C A R E N E W S James E. Davis patient and technologist. And we’re presenting you detailed information about each in this issue of Signa PULSE that you can put to immediate use on your Signa HDx system. • IDEAL – consistent, exceptional fat suppression for even the most challenging anatomies, solving the problem with chemical shift artifacts • Cube – the 3D, HD acquisition that allows you to view in any plane, eliminating operator variances and minimizing blurring to acquire complete data from scan – all while significantly reducing total exam time • 3D Dual Echo – Overcomes difficult imaging challenges, such as fatty liver disease, by acquiring images at the true TE at any Tesla strength All of these are industry leading applications … many developed in collaboration with our lead users. As we walk down the path of this new era in healthcare together, it’s exciting to look to the future. We’re working on some truly revolutionary ideas that have our engineers buzzing with excitement. But at GE Healthcare, we try to make sure that these ideas not only are exciting – but realistic. That’s why we’re focused on solutions that enable you to See more with better image quality. Do more with solutions that make sense and opportunities that expand your practice into other areas. And Expect more from your vendor – with service and solutions that won’t become obsolete. That is our promise – we look forward to moving into the future with you. • ARC – A major step forward in speed and accuracy, delivers a highly accelerated parallel imaging technique, enabling tight field-of-view (FOV) prescriptions • BrainSTAT – combined with diffusion imaging, provides an effective way to visualize the effects of neurological conditions, providing valuable treatment information faster James E. Davis Vice President and General Manager, Global MR Business GE Healthcare A GE Healthcare MR publication • Autumn 2007 5 The information contained in this document is current as of publication of the magazine. G E H E A LT H C A R E N E W S NEW PRODUCTS New Volume Acquisition Helps Clinicians Detect Small Lesions GE Healthcare introduces Cube™, a new volumetric fast spin echo (FSE) imaging sequence available on the Signa® HDxt 1.5T and 3T platforms. Optimized for T2, T2 FLAIR and Proton Density imaging, Cube captures the entire volume with high spatial, isotropic resolution. As a result, any view, plane or slice can be later reconstructed from a single acquisition with the same high resolution as the native plane. This new ability for volumetric imaging of the anatomy can result in fewer retakes that are often due to missing or misaligned slices or planes. It may also help radiologists to more consistently detect lesions as small as 2mm. The Cube sequence is based on modulated flip angles, which make very long echo train feasible. The typical image blurring and SAR are reduced, while high tissue contrast leads to conspicuous appearance of pathologies. Protocol settings are automatically optimized based on the anatomical region of interest (ROI) and MR sequence. Cube also provides excellent enhanced tissue contrast and specific absorption rate (SAR) management by staggering the delivery of energy to the patient/tissue. When used with GE’s innovative auto-calibrating, data-driven parallel imaging technique, ARC, clinicians will have the Isotropic volumetric imaging with Cube capability to acquire large high definition 3D data sets in relatively short time for a more efficient workflow. As part of the revolutionary HDxt platform, Cube completes GE’s volume portfolio to allow clinicians to provide the benefits of volume imaging for every study. The IDEAL Solution for Fat and Water Separation Representing a new paradigm in fat suppression, IDEAL is an innovative method for fat and water separation available exclusively on GE Healthcare’s Signa® HDxt 1.5T and 3.0T MR systems. IDEAL is a single acquisition technique that generates four images – water only, fat only, in phase and out of phase. This new sequence is particularly useful when imaging difficult areas of the anatomy, such as the orbits, brachial plexus, c-spine, extremities. IDEAL consistently separates fat from water in challenging anatomical areas, resulting in excellent image quality. Also, because IDEAL is a single acquisition technique, the in phase and out of phase images are inherently registered, leading to faster interpretation and higher diagnostic confidence. 6 A GE Healthcare MR publication • Autumn 2007 Developed in conjunction with Stanford Radiology and the University of Wisconsin-Madison Hospitals and Clinics, IDEAL is enabled for 2D FSE with PD, T1 or T2 contrast and 3D SPGR with T1 contrast. Unlike current methods, such as spectrally selective fat saturation and STIR, IDEAL is compatible with the new generation of phased array coils and parallel imaging techniques. The information contained in this document is current as of publication of the magazine. N E W P R O D U C T S G E H E A LT H C A R E N E W S Introducing the Next Generation of HD MR Just as high definition (HD) has transformed TV, HD MR enables new clinical capabilities by capturing higher resolution and consistently clear images for increased diagnostic confidence. GE Healthcare introduces Signa® HDxt to extend the concept of isotropic, volumetric imaging. HD Volumetric MR can help transform imaging by addressing some of the toughest issues facing MR imaging today. With advanced technology, new coils and applications, Signa HDxt provides high definition, complete data sets with enhanced clear contrast for overall better image quality within a shortened exam time. New applications driving volume data acquisition include: • Cube™, which quickly acquires isotropic resolution volume data that allows multi-plane reconstruction, while helping reduce the number of scans and total exam time • ARC, a fast, robust, auto-calibrating data-driven parallel imaging method that minimizes artifacts and significantly decreases sensitivity to motion, ideal for smaller field of view imaging • 3D Dual Echo, a volumetric, high signal-to-noise ratio imaging sequence that generates in-phase and out-of-phase images in a single breath hold acquisition even at 3.0T • IDEAL, a revolutionary HD technique for true fat and water separation provides uncompromising image clarity with consistent and robust fat suppression, especially in difficult areas of anatomy. A GE Healthcare MR publication • Autumn 2007 7 The information contained in this document is current as of publication of the magazine. G E H E A LT H C A R E N E W S EVENTS Calendar of Events GE looks forward to seeing you at the following events 8 Conference Dates Conference Center or Hotel City and State or Provence Country Web link San Antonio Breast Cancer Symposium Dec. 13-16 Henry B. Gonzalez Convention Center San Antonio, TX USA www.sabcs.org Society for Cardiovascular Feb. 1-3 Magnetic Resonance (SCMR) 11th Annual Scientific Sessions Hyatt Regency Century Plaza Los Angeles, CA USA www.scmr.org Vail 2008: MRI in Clinical Practice Feb. 10-15 Vail Marriot Mountain Resort & Spa Vail, CO USA www.educationalsymposia.com MRI 2008: Clinical Updates and Practical Applications Feb. 18-22 Rio Mar Beach Resort and Spa – Puerto Rico Wyndham Grand Resort Commonwealth www.cms.hms.harvard.edu of the USA American Society of Functional Feb. 27-29 Neuroradiology (ASfNR), 2nd Annual Meeting Rosen Shingle Creek Orlando, FL USA www.asfnr.org American Academy of Orthopaedic Surgeons 75th Annual Meeting Moscone Center San Francisco, CA USA www.aaos.org European Congress of Radiology Mar. 7-11 Austria Center Vienna Vienna Austria www.myesr.org The Breast Course Mar. 12-15 Fairmont Le Chateau Frontenac Quebec City, Quebec Canada www.thebreastcourse.com American College of Cardiology (ACC) 59th Annual Scientific Session Mar. 29-Apr. 1 McCormick Place Chicago, IL USA www.acc.org The Annual Meeting of Japan Radiological Society & The Annual Scientific Congress of Japanese Society of Radiological Technology Apr. 4-6 Pacifico Yokohama Yokohama, Kanagawa Japan www.secretariat.ne.jp 2008 3T MRI Whole Body Imaging Apr. 10-12 in Clinical Practice: Basic Fundamentals – Adv. Apps. Eden Roc, A Renaissance Beach Resort & Spa Miami Beach, FL USA www.educationalsymposia.com MRI of the Head & Spine 2008 National Symposium Apr. 28-30 The Venetian Resort-Hotel-Casino Las Vegas, NV USA www.educationalsymposia.com Magnetic Resonance Imaging 2008: National Symposium Apr. 28-May 2 The Venetian Resort-Hotel-Casino Las Vegas, NV USA www.educationalsymposia.com MRI of the Body & Heart 2008: National Symposium Apr. 30-May 2 The Venetian Resort-Hotel-Casino Las Vegas, NV USA www.educationalsymposia.com ISMRM Sixteenth Scientfic Meeting and Exhibition/SMRT Seventeenth Annual Meeting May 3-9 Metro Toronto Convention Centre Toronto, Ontario Canada www.ismrm.org Society of Breast Imaging May 8-10 Grande Lakes Resort Orlando, FL USA www.sbi-online.org American Society of Neuroradiology (ASNR), 46th Annual Meeting & NER Foundation Symposium May 31-June 5 Morial Convention Center New Orleans, LA USA www.asnr.org European Society of June 10-13 Gastrointestinal and Abdominal Radiology (ESGAR) 2008 Istanbul Conference & Exhibition Center Istanbul Turkey www.esgar.org Organization for Human Brain Mapping Melbourne Convention Center Melbourne Australia www.hbm2008.com Mar. 5-9 June 15-19 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. E D U C A T I O N G E H E A LT H C A R E N E W S GE Opens China’s First MR Application Academy With the deployment of more than 2,000 MR units across China, hospitals suffer from a shortage of trained technologists, physicists, radiochemists and radiologists specializing in MRI. To help accelerate this important area of growth and provide training and development in this pivotal field, GE Healthcare co-founded and opened the first MR Application Academy in Shanghai in collaboration with the Chinese Society of Radiology and the Chinese Society of Imaging Technology. The academy will provide a platform to meet the demand for training brought on by the rapid adoption of MRI technology throughout China. The Academy will focus on advancing MR clinical applications and promoting research utilizing techniques and applications among the Chinese research and academic communities. It will also provide essential, professional training for MRI technologists, radiologists and research scientists. Located at the GE China Technology Center, it is comprised of the MR Education Center China (MRECC), the Sino-U.S. MR Physics Center and the Sino-U.S. MR Molecular Imaging Center. “With the wholehearted support of China’s MR community and leaders in the MR field from the U.S., the Academy is the first and only institution dedicated to MRI training in China today,” stated Zhao Bin, Executive President of China MR Application Academy and Director of Shandong Medical Imaging Research Institute. “Our focus is on both the provision of opportunities for MR clinical practice and learning for front-line medical personnel, and on the establishment of a new scientific MR research mode for our large academic hospitals and research institutions. The China MR Application Academy is laying the foundation for the advancement of medical imaging within China.” Among the esteemed MRI professionals serving the Academy are co-presidents Professor Qi Ji, Chairman of the Chinese Society of Radiology and Dr. Thomas Foo, Manager of GE Global Research Center MRI Lab. More than 60 experts from China and the U.S. have also been appointed as professors at the Academy. To learn more about the academy, visit www.mriabc.org. A GE Healthcare MR publication • Autumn 2007 9 The information contained in this document is current as of publication of the magazine. G E H E A LT H C A R E N E W S USER MEETINGS 3.0T Continues to Bring Users Together Signa 3.0T made easy in the “Big Easy” As part of the conference “3.0T MRI: Whole Body Imaging in Clinical Practice,” in New Orleans, GE Healthcare hosted a fourth 3.0T users meeting on April 28, 2007. The meeting was geared to help optimize the clinical use of the Signa® 3.0T MR System. Guest speaker, Sheetal S. Desai, RT (R)(MR), Chief MR Technologist, Edison Imaging Associates (Edison, NJ), discussed MR imaging tips and techniques for optimizing breast imaging, specifically with the use of new fat sat pads. Bryan Mock, PhD, GE Global 3.0T Product Manager, provided an update on portfolio enhancements and a glimpse into the continued future development of Signa 3.0T systems. Mike Pellerin, GE Clinical MR Specialist, discussed how to maintain T1 contrast at 3.0T with different alternatives, such as Spin Echo, FSPGR and T1 FLAIR. He also showed imaging strategies to address the dielectric effect at 3.0T. Pam Sandow, MR QA Specialist, presented artifact identification and management at 3.0T while Carol Maher, GE TiP Applications Specialist, presented the Succeed Program, a training concept designed to help users define a new strategy that can maximize the breadth and depth of clinical applications at 3.0T. 10 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. U S E R M E E T I N G S G E H E A LT H C A R E N E W S Sprechen sie 3.0T? A packed house produced an evening of sharing ideas and information at The Global Signa 3.0T Users Event during the International Society for Magnetic Resonance in Medicine (ISMRM), held May 19-25, 2007 in Berlin, Germany. Users were presented with an overview of the Signa 3.0T product portfolio, clinical imaging techniques, advanced neuro applications and technical performance. Bryan Mock, PhD, GE Global 3.0T Product Manager welcomed the 140-plus Signa 3.0T users with an update on new portfolio enhancements. He also unveiled plans for future enhancements to Signa 3.0T MR Systems. Lawrence Tanenbaum, M.D., FACR, Section Chief MRI, CT and Neuroradiology, Edison Imaging and JFK Medical Center, presented ultra high resolution imaging techniques using the new Cube™ volumetric imaging sequence at 3.0T. He also demonstrated robust water separation imaging techniques in a variety of anatomies. Steve Williams, PhD, Professor of Imaging Sciences, Institute of Psychiatry at Maudsley, London, UK, discussed advanced neuro imaging techniques, specifically applications in fMRI and diffusion imaging. Graeme McKinnon, PhD, Applied Science Lab, GE Healthcare talked about the technical performance of “B1 Shimming & the Dielectric Effect.” Gearing up for Signa Koshien Signa® Users in Japan have held nearly 60 users meetings in the first three quarters of 2007. These meetings include preliminary contests to nominate regional representatives for Japan’s Signa Koshien championship meeting, scheduled for December 8, 2007. Thirteen representatives from six regional areas will present topics in neurology, body, vascular and MSK and tips on generating better image quality and reducing artifacts and scan time. The 2007 Signa Koshien event, open to all GE Healthcare Signa users from 0.2T to 3.0T, will be held at Tokyo Mid Town on December 8, 2007 from 15:00 to 19:00. Of great interest to users are topics on non contrast enhanced MR Angiography (MRA) and PROPELLER HD™ technology. To further address these topics and more, GE launched a new Signa Users meeting website that can be found at http://gecommunity.on.arena.ne.jp/signa-l/. Over 400 Signa Users in Japan registered within the first six months, averaging 1,000 visits each month. Attendees reported they were impressed with both the diversity and depth of the information shared. The event followed with a reception dinner where users further discussed applications and challenges with the guest speakers, GE Scientists and Advanced Clinical MR specialists. GE Healthcare would like to thank Mitsuyuki Takahashi, RT, the leader of Kanagawa Signa Users meeting, the first group to hold a users meeting in Japan. Takahashi is the “father” of Signa Koshien and his continued leadership drives the success of this country-wide event. He maintains a web site on MR imaging, including an introduction to the Kanagawa Signa Users meeting, that can be found by visiting www.asahi-net.or.jp/~tv4m-tkhs/index.html. A GE Healthcare MR publication • Autumn 2007 11 The information contained in this document is current as of publication of the magazine. G E H E A LT H C A R E N E W S NEW PRODUCTS New Volume Acquisition Helps Clinicians Detect Small Lesions GE Healthcare introduces Cube™, a new volumetric fast spin echo (FSE) imaging sequence available on the Signa® HDxt 1.5T and 3T platforms. Optimized for T2, T2 FLAIR and Proton Density imaging, Cube captures the entire volume with high spatial, isotropic resolution. As a result, any view, plane or slice can be later reconstructed from a single acquisition with the same high resolution as the native plane. This new ability for volumetric imaging of the anatomy can result in fewer retakes that are often due to missing or misaligned slices or planes. It may also help radiologists to more consistently detect lesions as small as 2mm. The Cube sequence is based on modulated flip angles, which make very long echo train feasible. The typical image blurring and SAR are reduced, while high tissue contrast leads to conspicuous appearance of pathologies. Protocol settings are automatically optimized based on the anatomical region of interest (ROI) and MR sequence. Cube also provides excellent enhanced tissue contrast and specific absorption rate (SAR) management by staggering the delivery of energy to the patient/tissue. When used with GE’s innovative auto-calibrating, data-driven parallel imaging technique, ARC, clinicians will have the Isotropic volumetric imaging with Cube capability to acquire large high definition 3D data sets in relatively short time for a more efficient workflow. As part of the revolutionary HDxt platform, Cube completes GE’s volume portfolio to allow clinicians to provide the benefits of volume imaging for every study. The IDEAL Solution for Fat and Water Separation Representing a new paradigm in fat suppression, IDEAL is an innovative method for fat and water separation available exclusively on GE Healthcare’s Signa® HDxt 1.5T and 3.0T MR systems. IDEAL is a single acquisition technique that generates four images – water only, fat only, in phase and out of phase. This new sequence is particularly useful when imaging difficult areas of the anatomy, such as the orbits, brachial plexus, c-spine, extremities or areas of anatomy with metal. IDEAL consistently separates fat from water in challenging anatomical areas, resulting in excellent image quality. Also, because IDEAL is a single acquisition technique, the in phase and out of phase images are inherently registered, leading to faster interpretation and higher diagnostic confidence. 6 A GE Healthcare MR publication • Autumn 2007 Developed in conjunction with Stanford Radiology and the University of Wisconsin-Madison Hospitals and Clinics, IDEAL is enabled for 2D FSE with PD, T1 or T2 contrast and 3D SPGR with T1 contrast. Unlike current methods, such as spectrally selective fat saturation and STIR, IDEAL is compatible with the new generation of phased array coils and parallel imaging techniques. The information contained in this document is current as of publication of the magazine. N E W P R O D U C T S G E H E A LT H C A R E N E W S Introducing the Next Generation of HD MR Just as high definition (HD) has transformed TV, HD MR enables new clinical capabilities by capturing higher resolution and consistently clear images for increased diagnostic confidence. GE Healthcare introduces Signa® HDxt to extend the concept of isotropic, volumetric imaging. HD Volumetric MR can help transform imaging by addressing some of the toughest issues facing MR imaging today. With advanced technology, new coils and applications, Signa HDxt provides high definition, complete data sets with enhanced clear contrast for overall better image quality within a shortened exam time. New applications driving volume data acquisition include: • Cube™, which quickly acquires isotropic resolution volume data that allows multi-plane reconstruction, while helping reduce the number of scans and total exam time • ARC, a fast, robust, auto-calibrating data-driven parallel imaging method that minimizes artifacts and significantly decreases sensitivity to motion, ideal for smaller field of view imaging • 3D Dual Echo, a volumetric, high signal-to-noise ratio imaging sequence that generates in-phase and out-of-phase images in a single breath hold acquisition even at 3.0T • IDEAL, a revolutionary HD technique for true fat and water separation provides uncompromising image clarity with consistent and robust fat suppression, especially in difficult areas of anatomy. A GE Healthcare MR publication • Autumn 2007 7 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE VOLUMETRIC IMAGING – HDXT Volumetric Imaging Magnetizes Radiology GE Healthcare presents a paradigm shift by re-imagining volumetric MR The History of Volume Imaging GE Healthcare has long been a leader in bringing volumetric imaging to clinical practice. In fact, GE launched one of the world’s first volumetric ultrasound systems in the late 1980’s. Subsequent introductions of the LOGIQ™ 9, Voluson™ E8 and Vivid™ 7 Dimension products have helped redefine ultrasound with new volume acquisition capabilities. GE’s LightSpeed® VCT brought volume imaging to the forefront of CT with advanced applications that enabled clinicians to view the body as never seen before. Building upon this platform, GE Healthcare brought together innovative, advanced cardiac and neurology applications with the introduction of the LightSpeed VCT XT configuration, further extending the clinical capability of volume imaging. GE continues to exhibit leadership in volumetric imaging with the introduction of a new dimension to MR. High resolution, isotropic volume imaging changes the way image data is acquired and reviewed, such as providing new clinical benefits for visualizing small lesions and improving workflow efficiency with the ability to reconstruct the 3D volume data into any plane or slice at a later time while maintaining the same high image resolution as the native plane. Just as high definition (HD) has transformed television (TV), HD MR is enabling new clinical capabilities by capturing higher resolution and consistently clear images for increased diagnostic confidence. Today, GE Healthcare introduces the Signa® HDxt and the concept of HD isotropic, volumetric imaging. Volumetric imaging is not new to MR. GE introduced MR volume applications in the 1990s. While the concept was very attractive, MR platforms, gradient technology and computational processing power for acquiring and postprocessing these images were not yet ready from a technical standpoint. At the time, 3D MR was hindered by low resolution, long scan times and slow image reconstruction/post-processing. 12 A GE Healthcare MR publication • Autumn 2007 Since the turn of the decade, advancements in information technology created an environment suitable for handling the large data sets generated by HD volumetric imaging. Specialized coils for certain anatomic areas and faster, more powerful MR platforms enabled rapid acquisition of signal-rich data, which led to the first break-through, clinically-relevant volumetric applications such as TRICKS™, LAVA™ and VIBRANT®. However, until now these volumetric MR applications were mostly applied for a specific use and considered complementary to standard 2D MR acquisitions. A New Dimension to MR Today, with the Signa HDxt and several new 3D applications, GE builds on the promise of HD to add a new dimension to MR imaging. Clinicians will now have access to a solution that makes it possible to conduct the entire MR exam by exclusively applying volumetric MR techniques. HD volume MR delivers sub-millimeter resolution with gapless data volume and point-and-shoot simplicity to improve diagnostic confidence and reduce exam time. The HD Volume Revolution The new volumetric HD MR sequence Cube™ provides sub-millimeter isotropic resolution and enhanced tissue contrast for high definition detail to help clinicians detect small lesions earlier. The complete volume of data can be reconstructed in any view or plane without compromising spatial resolution. In comparison, conventional 2D image acquisitions typically provide discrete slices with gaps in one plane only. Since 2D images are acquired in one sagittal, coronal, axial or oblique plane, critical data vertical to the acquired plane or contained within the gap between the acquired slices could be missed. The information contained in this document is current as of publication of the magazine. VOLUME TRIC IMAGING – HDX T CLINICAL VALUE The new Volumetric HD MR sequence Cube provides sub-millimeter isotropic resolution and enhanced tissue contrast for high definition detail to help clinicians detect small lesions earlier. Flexible, clinical region-of-interest optimized sequence protocols simplify and speed up acquisition while generating consistent, high definition diagnostic quality images. This is accomplished independent of the patient for reliable image acquisition by the MR technologist. With the addition of Cube, Signa HDxt boasts a complete portfolio of dedicated volumetric MR applications for a vast array of clinical areas, which is likely to change the paradigm of MR imaging. GE is leading the charge with new automated, optimized MR protocols such as Cube, IDEAL and 3D Dual Echo. These join the ranks of GE’s other volumetric MR sequences, including: LAVA and VIBRANT-XV™ for anatomy; TRICKS for flow; 3D PROBE/PROSE for MR spectroscopy; and BRAVO and BrainWave™ Fusion for fMRI/DTI brain mapping. The advantages of the 3D HD Volumetric MR include: • Helps detect small lesions • No missing planes, slices or gaps in data, which can minimize retakes • High tissue contrast for conspicuous lesions • Consistent IQ through automated and ROI-optimized protocols • Reduced exam time due to a single volume acquisition replacing several discrete sliceby-slice/plane-after-plane acquisitions A GE Healthcare MR publication • Autumn 2007 13 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE VOLUMETRIC IMAGING – CUBE The Clinical Proof of 2D Versus 3D During the 45th Annual Meeting of the American Society of Neuroradiology, held in Chicago June 9 -12, 2007, Lawrence N. Tanenbaum, M.D., FACR, Section Chief MRI, CT and Neuroradiology, New Jersey Neuroscience Institute, Edison Imaging, discussed differences between 2D and 3D MR image acquisitions. Dr. Tanenbaum and his associates use volume acquisitions every day in their practice, such as imaging of multiple sclerosis (MS) and for imaging of hippocampus in epilepsy. Regarding his recent experience with GE’s new volumetric imaging applications, he remarked, “We are about to enter an era with more exciting techniques. The most impactful, new volumetric technique is Cube™. ” Significant to this application are pulse sequence changes that require shorter RF pulses and provide tighter echo spacing, leading to less blur and the ability to use longer echo trains while maintaining signal-to-noise ratio (SNR), he explained. “Clever modulation of the flip angle during acquisition tends to actually eliminate a lot of the blur you get with fast spin echo, and provides a driven equilibrium effect that boosts SNR,” he added. Cube leverages the resultant reshaped signal decay state with very long echo trains boosting speed while maintaining SNR. Historically, a potential pitfall for MR acquisitions has been long acquisition times, which limit practical application in many clinical settings and can also lead to an increase in motion artifacts. However, this is circumvented with the development of an advanced, data-driven parallel imaging technique for use with Cube. ARC* uses information available in each plane or dimension to help improve reconstruction accuracy, lessen motion artifacts and reduce calibration lines. Figure 1. Moderate grade glioma Cube 1.5T and fibertrak images of three-year-old male *ARC: Autocalibrating Reconstruction for Cartesian imaging 14 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. VOLUME TRIC IMAGING – CUBE CLINICAL VALUE “This application is changing the way we scan at Edison Imaging and Cube has already replaced other techniques in my practice.” Dr. Lawrence Tanenbaum Combining ARC with Cube acquisitions, Dr. Tanenbaum achieved acceleration factors of four to nine, providing isotropic whole brain acquisitions in approximately three minutes. “We’ve experienced very impressive results. “Although Cube is a very sophisticated sequence, this application is easy-to-use, robust and very fast,” Dr. Tanenbaum said. When used with ARC, he was able to routinely acquire 1.2 mm to 0.6 mm isotropic voxels with T2 and FLAIR contrast. “The reconstructed very thin, gap-free slices facilitate high resolution data interrogation of complete volume data – something we do not have with 2D.” He noted the clinical result is the ability to see MS lesions as small as 2 mm. “This application is changing the way we scan at Edison Imaging,” Dr. Tanenbaum said, “and Cube has already replaced other techniques in my practice.” Lawrence N. Tanenbaum, M.D., FACR Lawrence N. Tanenbaum, M.D., FACR, is Chief of MR, CT and Neuroradiology at Edison Imaging Associates and Solaris Health Systems. For over 30 years, the radiologists of Edison Imaging have led the way in providing the medical communities of central New Jersey with a full range of imaging services, utilizing the latest, most advanced technologies, including GE’s Signa HDxt 3.0T and 1.5T MR Scanners. According to Dr. Tanenbaum, other potential uses of Cube are with fMRI and Tractography, providing excellent fusion and automatic segmentation results with 3D rather than 2D. Volumetric techniques have the power to drive quantitative assessments that are impractical and “almost inappropriate to do with 2D because of thick sections and intervening gaps innate to 2D imaging. With capabilities, it can become a gold standard acquisition.” For Dr. Tanenbaum, the benefits of volumetric MR imaging go beyond speed and the ability to reformat. “The susceptibility artifact that propagates in plane does not propagate through plane, so you get a pristine, orbital floor and skull base.” He further believes that volumetric multi-plane imaging can help minimize additional scans, reducing total scan times in many cases. Yet, the true value lies in the ability to arm clinicians with a better diagnostic tool. “You can’t argue against thin-slice, gap-free studies for the detection of disease. This will change the way we scan.” Figure 2. Cube FLAIR and FiberTrak at 3.0T Glioma Figure 3. Cube T2 3.0T Glioma All clinical images courtesy of Lawrence N. Tanenbaum, M.D., FACR, Edison Imaging. A GE Healthcare MR publication • Autumn 2007 15 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE FAT S AT – I D E A L Consistent, Reliable, Fat-Suppressed Imaging Even with Difficult Anatomy In MR images, fat appears bright and can obscure or mimic pathology, so most clinical protocols use methods to suppress fat, improving the conspicuity of underlying abnormalities. There are many instances, however, where it would be advantageous for clinicians to directly visualize fat. For example, when imaging a tumor containing fat, the typical protocol is to obtain images with and without fat suppression. To provide robust, water-only images that also retain important information from fat, it is critical to have methods for robust, uniform separation of water and fat. Some limitations of traditional fat suppression techniques are outlined in the adjacent sidebar. Perhaps most important to note with these techniques, all fat signal is lost along with useful diagnostic information. To address this need, GE Healthcare developed a new technique, IDEAL*, in collaboration with the University of Wisconsin and Stanford University. It is available for use on the Signa HDx 1.5T and 3.0T MR systems. Scott Reeder, M.D., PhD, Division Chief of MRI, University of Wisconsin-Madison Hospitals and Clinics, is one of the inventors and patent holders for IDEAL. “IDEAL is robust in challenging areas,” Dr. Reeder said. “We can achieve excellent fat suppression and also directly visualize the fat imaging.” The technique is related to traditional 3-point Dixon methods, acquiring three images at slightly different echo times to generate phase shifts between water and fat. Although three echoes are necessary, the effective number of excitations (NEX) for the water and fat images is three; therefore, IDEAL has the maximum possible signal-to-noise (SNR) efficiency, using all images efficiently in the separated water and fat images. According to Dr. Reeder, the key advantage of IDEAL is the ability to use parallel imaging. “We can’t use parallel imaging with traditional 3-point Dixon methods.” Also, IDEAL is compatible with the newer generation of phased array *IDEAL: Iterative Decomposition of water/fat using Echo Asymmetry and Least-squares estimation 16 A GE Healthcare MR publication • Autumn 2007 Limitations of traditional fat suppression techniques • Spectrally selective fat sat methods fail in challenging anatomical areas, such as the neck, extremities, offisocenter imaging, and large field-of-view (FOV) imaging. This is due to local magnetic field inhomogeneities caused by susceptibility differences at air-tissue interfaces and by the unfavorable geometry, or inhomogeneities, induced by the presence of metallic implants. Failed fat saturation can also cause inadvertent saturation of the water signal (the signal of interest), obliterating important anatomy or pathology and rendering images non-diagnostic. Spatial-spectral or “water-excitation” pulses suffer from the same drawbacks as fat-saturation methods. • Short TI recovery (“STIR”) imaging uses an inversion pulse to null short T1 species such as fat, but in the process alters contrast and reduces SNR. STIR images are inherently T1 weighted, and should not be used for post-contrast imaging because the shortened T1 of enhancing tissue may cause inadvertent suppression of important pathology. STIR provides very uniform fat suppression and is commonly used with T2 weighted imaging; however, the poor SNR performance and inability to perform post-contrast T1 weighted imaging are highly limiting. coils and optimized for the best possible SNR. With IDEAL it is also possible to use arbitrary echo spacing and arbitrary numbers of echoes (N>=3), while Dixon methods are limited to images acquired when water and fat signals are acquired in and out of phase. As a result, the echo shifts are optimized for the highest possible SNR performance, which further accelerates the acquisition. “The SNR penalty with parallel imaging is offset by the increased SNR with IDEAL,” he added. The information contained in this document is current as of publication of the magazine. FAT S AT – I D E A L C L I N I C A L VA L U E Fat Sat failures Scott Reeder, M.D., PhD Fat Sat Scott Reeder, M.D., PhD, is Division Chief of MRI, University of Wisconsin–Madison Hospitals and Clinics. IDEAL: water (uniform fat suppression) About University of Wisconsin-Madison Another advantage of IDEAL is its ability to capture high quality images in a point-and-shoot way. Dr. Reeder said, “Fat can be consistently and reliably separated from water. This can lead to a decrease in the number of sequences within our protocols.” He also noted the reliability of IDEAL reduces the need to repeat scans that previously resulted from failed fat saturation with traditional methods or STIR. In addition, the separated water and fat images can be recombined into “in-phase” and “out-of-phase” images, which are commonly acquired as two separate acquisitions. This should further reduce overall protocol time and provide additional information to the radiologist. A third benefit of IDEAL is the elimination of artifacts, and chemical shift. In-phase, or non fat-suppressed, images are corrected for chemical shift misregistration of fat, thereby allowing low bandwidth acquisitions and reduced NEX. Dr. Reeder notes that the higher SNR with less artifact produces higher quality images that give the radiologist more confidence. “IDEAL can unambiguously identify water and fat,” he added. Water, fat, in-phase and out-of-phase images are inherently co-registered, which can lead to faster interpretation and higher diagnostic confidence, particularly in difficult areas of anatomy such as: • Orbits • Brachial plexus • C-spine • Extremities (ankle/wrist/foot) • Off iso-center applications (shoulder/hip) T2W Fat Sat FSE T2W IDEAL FSE UW Health, the academic health system for the University of Wisconsin, offers more than 60 locations throughout the state, including the renowned University of Wisconsin Hospitals and Clinics and University of Wisconsin Children’s Hospital in Madison. This comprehensive system of healthcare providers serves patients at more than 60 clinical locations throughout the state. University of Wisconsin Hospitals and Clinics is a 471-bed facility that ranks among the finest academic medical centers in the United States. The University of Wisconsin Hospitals and Clinics offers more than 800 active medical staff and more than 80 outpatient clinics. The hospital has six intensive care units (trauma and life support, pediatric, cardiac, cardiothoracic, burn, neurosurgery) with 74 total beds, and is one of only two organizations in Wisconsin with designated Level One adult and pediatric trauma centers. T2W STIR Brachial Plexus Imaging – 1.5T, PD Weighted, 2D Fast Spin Echo A GE Healthcare MR publication • Autumn 2007 17 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE FAT S AT – I D E A L Clinical Applications A common indication for MR imaging is for the detection of masses. For example, in the female pelvis, endometriomas are often bright on T1 weighted imaging, while an ovarian dermoid has fat, which also appears bright on T1 weighted imaging. Most MR imaging protocols include two T1 weighted sequence scans – one with and another without fat supression. “With IDEAL, it requires only one acquisition to separate both water and fat signals,” Dr. Reeder said. “We can help increase the level of diagnostic confidence by directly visualizing the fat. This is a unique capability of IDEAL.” Another difficult imaging area is the brachial plexus. This critical area of the anatomy is prone to the invasion of lung tumors (eg. Pancoast tumor). “Using traditional fat saturation methods, MRI tends to fail in this area,” Dr. Reeder explained. “We don’t use STIR because it is incompatible with post-contrast T1 weighed imaging and its poor SNR performance.” IDEAL, he said, is an excellent solution for this clinical study. T1W Fat Sat FSE T1W IDEAL FSE T1W Fat Sat FSE T1W IDEAL FSE Post-surgical Cervical Spine: Neurofibromatosis T1W Fat Sat FSE T1W IDEAL FSE Benefits of IDEAL • Patient – potentially reduce “on the table” scan time, • Technologists – reduce number of repeat scans • Radiologists – higher diagnostic image quality for increased confidence • Administration – potential for increased throughput • Referring physician – better image quality Coronal Fse-xl T2 fat suppressed images (fov 30cm) demonstrates inhomogeneous fat suppression in the slice anterior–posterior direction 18 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. GE Healthcare The Tipping Point in Healthcare. The Tipping Point in Healthcare – a compelling and convincing argument by GE Healthcare President and CEO Joe Hogan for reshaping healthcare through five powerful initiatives: • Focusing on Early Health, not late disease • Turning information into insight • Measuring healthspan, not lifespan • Increasing the transparency of quality and cost • Committing to equity in healthcare access To download a copy of The Tipping Point in Healthcare visit www.gehealthcare.com/tippingpoint. “To take healthcare into the future, we don’t have to wait for technologies that will be available in 2025. We need only look at the technologies we have today, and act.” Joe Hogan President and CEO, GE Healthcare imagination at work The information contained in this document is current as of publication of the magazine. CLINICAL VALUE VOLUMETRIC IMAGING – DWI & DTI High-Resolution, Isotropic-Voxel Acquisition Technique Improves Quality and Utility of Diffusion-Weighted and Diffusion Tensor Imaging By Makoto Sasaki, M.D., Associate Professor, Advanced Medical Research Center, Iwate Medical University Introduction Volume Diffusion Imaging Technique Image quality in diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) tends to be deteriorated by echo planar imaging (EPI)-related image distortions and artifacts, particularly in the case of coronal images and at high fields of 3.0T, even when a parallel imaging technique is applied. This disadvantage prevents clinicians from assessing changes in structures adjacent to the skull base, such as the medial temporal lobe and frontal base. Partial volume effects in DWI/DTI also affect the accuracy in the calculation of diffusion parameters and in the generation of tractographs. A new DWI/DTI technique enables the generation of highresolution isotropic-voxel “volume” datasets that can reduce partial volume effects and susceptibility-related distortions/ artifacts near the skull base. Further, we demonstrate the clinical efficacies of images generated from these volume datasets using multiplanar reconstruction, volume rendering, color-coded axonography and DTI tractography. To obtain high-resolution isotropic-voxel DWI/DTI data, we utilized a simple two-dimensional (2D) acquisition approach, instead of a three-dimensional (3D) approach, with ultra thin sections as in the case of multidetector-row computed tomography (MDCT). Images were obtained on a Signa® HD 3.0T with an eight-channel head coil using the following pulse sequences: axial single-shot spin-echo EPI; repetition time/echo time, 12000–17000/62.5; 3 or 6 motion-probing gradient (MPG) directions with a b value of 1000 s/mm2; a matrix size of 128 x 128, a field of view of 20 cm, a slice thickness of 1.6 mm with no interslice gaps, resulting isotropic voxels of 1.6 x 1.6 x 1.6 mm; 4 averaged; an array spatial sensitivity encoding technique (ASSET), reduction factor of 2; and 80 to 90 slices for the coverage of the entire brain with an acquisition time ranging from 6 min, 24 sec to 8 min, 30 sec.1,2 Coronal DWI Asset (-) Coronal DWI Asset (+) Volume DWI (MPR) Figure 1. Volume DWI can decrease geometric distortion and susceptibility artifacts in coronal images. 20 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. VOLUME TRIC IMAGING – DWI & DTI CLINICAL VALUE Advantages of Volume Diffusion Imaging The whole-brain high-resolution isotropic-voxel DWI/DTI acquisition technique using ultra thin axial sections has several advantages over conventional DWI/DTI. These include: reduction of geometric distortions and susceptibility artifacts near the skull base; decrease in partial volume effects that can affect the accuracy in the calculation of quantitative diffusion parameters and in the delineation of tractographs; and capability of multiplanar reconstruction and further image processing. Among them, geometric distortions in the craniocaudal direction and susceptibility artifacts near the skull base on coronal images are dramatically decreased owing to the thin-slice axial images obtained with this technique.1 On the coronal images generated from the volume DWI data, as compared with conventional coronal DWI, the structures of the medial temporal lobe and frontal base showed minimal deformities and tolerable susceptibility artifacts with preservation of the in-plane spatial resolution (Figure 1). Clinical Applications of Volume Diffusion Imaging The volume diffusion imaging technique enables sophisticated multimodal interactive visualization and interpretation, which has been nearly impossible to achieve using conventional DWI/DTI. Once the volume dataset is obtained, we can observe trace maps, apparent diffusion coefficient (ADC) maps, fractional anisotropy (FA) maps and color-coded axonography images of patients with neurological conditions such as stroke, brain tumors or degenerative disorders by using paging, multiplanar reconstruction or volume-rendering techniques (Figures 2 and 3). Makoto Sasaki, M.D. Makoto Sasaki, M.D., is Associate Professor, Advanced Medical Research Center, Iwate Medical University, School of Medicine. He received his medical degree and doctorate of medical sciences from Iwate Medical University. Dr. Sasaki currently serves as trustee of the Japanese Society of Magnetic Resonance in Medicine and the Japanese Society of Neuroradiology. He is an active member of the Japan Radiological Society, ISMRM, RSNA, Japan Stroke Society, Japanese Society of Neurology and Japanese Society for Detection of Asymptomatic Brain Diseases. Dr. Sasaki plays an important role in the standardization of the stroke imaging through ASIST-Japan (Acute Stroke Imaging STandardization group Japan) activities (http://asist.umin.jp/index-e.htm). He is also leading to develop a neuromelanin-sensitive MRI technique that can visualize alteration of catecholamine nuclei in mental disorders. A Certificate of Merit was awarded to him and his colleagues for volume diffusion imaging (NR4667) and neuromelanin imaging (NR4704) at RSNA2006. About Iwate Medical University, Morioka, Iwate Pref Figure 2. Volume DWI enables multiplanar reconstruction and further postprocessing, such as volume rendering (Provided by Okayama Kyokuto Hospital). Iwate Medical University, founded in 1928, and its affiliate hospital (1051 beds) has been the core healthcare and research center in northern Japan through the establishment of several key facilities, including Memorial Heart Center (1997) and Advanced Medical Research Center (1999). The Advanced Medical Research Center, headed by Dean and Chairman Prof. Akira Ogawa, was established primarily for the investigation of neuroscience and neuroimaging, and has made significant contributions to research of the brain with High Field 3.0T MRI and PET. A GE Healthcare MR publication • Autumn 2007 21 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE VOLUMETRIC IMAGING – DWI & DTI Figure 3. Volume DWI/DTI can visualize minute structures that belong to the limbic system. trace FA c c i trace FA c c i a a e e h h e * e * a: amygdala, c: cingulum, e: entorhinal cortex, h: hippocampus, i: substantia innominata, *parahippocampal white matter containing the perforant path, arrows: anterior commissure. precommissural fornix amygdalofugal fibers anterior commissure body of fornix crus of fornix precommissural fornix column of fornix body of fornix column of fornix anterior commissure fimbria crus of fornix amygdalofugal fibers fimbria Figure 4. Multimodal volume neuroimaging combining 3D-FSPGR, Cube™ (T2WI and FLAIR), and volume DTI can bring about a paradigm shift from a 2D to a 3D approach in clinical neuro-magnetic resonance imaging. The precise quantitative evaluation of minute structures of the limbic system is a promising application of the volume diffusion technique. The ADC or FA in small limbic structures, such as the hippocampus, entorhinal cortex and substantia innominata, can be measured because the increase in spatial resolution and the decrease in susceptibility distortions/ artifacts synergistically improve image quality (Figure 3). In addition, the precision of the segmentation of small limbic 22 A GE Healthcare MR publication • Autumn 2007 fibers, such as the fornix, using DTI tractography can be improved; this can influence the accuracy of the estimation of the ADC and FA in these fibers.2 The volume diffusion technique can be useful for detecting subtle changes in the small limbic structures in patients with early Alzheimer’s disease, temporal lobe epilepsy or other disorders that have barely been assessed by conventional DWI/DTI techniques. The information contained in this document is current as of publication of the magazine. VOLUME TRIC IMAGING – DWI & DTI CLINICAL VALUE 3D-FSPGR Cube T2WI Cube FLAIR Gd 3D-FSPGR Volume DTI (FA color map) Volume DTI (tractography) cingulum Figure 5. Conclusion Further, we believe that even in routine clinical practice, conventional neuroimaging protocols that primarily utilize 2D imaging at 3.0T can be replaced by an advanced protocol involving the acquisition of multimodal volume data sets, including 3D fast spoiled gradient-recalled acquisition in the steady state (3D-FSPGR), fast spin-echo with extended echo-train acquisition (Cube) and volume DWI/DTI (Figure 4). Volume diffusion imaging with high-resolution, isotropic voxels is effective in avoiding partial volume effects and EPI-related distortions and artifacts that are particularly prominent in the coronal directions and at high fields. It also enables the elucidation of subtle abnormalities in minute brain structures in central nervous system disorders using multiple diffusion parameter maps visualized by multiplanar reconstruction, tractography and further image processing. Acknowledgement The author thanks Mr. Wataru Takao, Okayama Kyokuto Hospital, Dr. Shunrou Fujiwara, Advanced Medical Research Center, Iwate Medical University, and Dr. Ryonoshin Hirooka, Department of Neurosurgery, Iwate Medical University, for their generous help in MR imaging and postprocessing. DTI color maps and tractographs were generated by VOLUME-ONE/dTV2 provided by the Department of Radiology, University of Tokyo (http://www.volume-one.org). References 1. Fujiwara S, Sasaki M, Kanbara Y, et al. Improvement of geometric distortion in coronal diffusion-weighted and diffusion tensor imaging by using a whole-brain isotropic-voxel acquisition technique at 3 Tesla. Magn Reson Med Sci 2007 (in press) 2. Fujiwara S, Sasaki M, Kanbara, Y, et al. Feasibility of 1.6-mm isotropic voxel diffusion tensor tractography in depicting limbic fibers. Neuroradiology 2007 (in press) A GE Healthcare MR publication • Autumn 2007 23 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE ABDOMINAL IMAGING – 3D DUAL ECHO One Breath Away from Volumetric In-Phase, Opposed-Phase Fat/Water Imaging By Elmar M. Merkle, M.D., Professor of Radiology, Director of Body MR Imaging, Medical Director, Center for Advanced MR Development, Duke University Medical Center, Department of Radiology T1-weighted gradient-echo in-phase and opposed-phase imaging is routinely used in abdominal MRI to identify regions of diffuse or geographic fatty infiltration, as well as areas of focal fatty sparing in the liver. In addition, this sequence can be valuable in the characterization of fat containing liver lesions such as hepatic adenomas or hepatocellular carcinomas. In- and opposed-phase imaging can also be helpful for detecting pathologic entities such as hemosiderosis and hemochromatosis. Here, a substantial loss in hepatic signal intensity can be detected on the image with the longer echo time due to associated T2* effects. Finally, susceptibility artifacts from surgical clips, metallic debris or gas may be easily identified on this dual echo sequence. 24 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. ABDOMINAL IMAGING – 3D DUAL ECHO CLINICAL VALUE Historically, the in-phase and opposed-phase images were acquired within separate breath holds, which caused suboptimal registration between the corresponding images. While current 2D dual echo techniques are now being acquired within a single breath hold, these 2D techniques rely on a relatively large flip angle to achieve adequate T1 weighting and desired hepatosplenic image contrast. In addition, slice thickness is usually in the range of 6 to 8 mm with an interslice gap of 1 to 2 mm, to allow for adequate coverage of the entire liver within a single breath hold. This through-plane spatial resolution allows for suboptimal image quality of multiplanar reconstructions only. At 3.0T, the 2D approach oftentimes exceeds limits in the specific absorption rate requiring either a decrease of the flip angle, decrease of the number of images, or an increase of the repetition time. None of these requirements is desirable as either the coverage is decreased, the image contrast is altered, or the data acquisition time is prolonged. Even worse is the fact that the data acquisition of the first opposed-phase echo at 1.2 msec and the first in-phase echo at 2.4 msec usually requires a substantially higher receiver bandwidth. Therefore, in addition to the first opposed-phase echo, the second in-phase echo at 4.8 msec is usually acquired which leads to accentuated T2* effects. 3D Dual Echo is a new 3D FSPGR sequence from GE Healthcare that produces fat/water in-phase and opposed-phase images in a single breath hold. This sequence allows the acquisition of the first opposed-phase and the first in-phase image. This allows perfect registration between corresponding images and is also helpful in the visualization of T2* effects and susceptibility artifacts. Using the 3D Dual Echo sequence for abdominal imaging can be particularly important for the characterization of hepatic and adrenal lesions, and represents a significant step forward in the clinical utilization of 3.0T MR. With improved through-plane resolution of about 4 mm without an interslice gap, this new pulse sequence also allows for excellent multiplanar reconstructions. Clinical Cases The following case studies demonstrate the value of the 3D Dual Echo sequence. Case 1 Dr. Elmar Merkle Elmar Merkle is Professor of Radiology and Head of Body Magnetic Resonance Imaging and heads the Center for Advanced Magnetic Resonance Development at Duke University. In the mid 1990s, he conducted his MR research fellowship in the laboratory of Professor Jonathan Lewin in Cleveland, where he made significant contributions to the field of interventional MR imaging. Dr. Merkle is a fellow of the Society of Computed Body Tomography and Magnetic Resonance (SCBT), and a member of the Radiologic Society of North America (RSNA), the International Society for Magnetic Resonance in Medicine (ISMRM), the American Roentgen Ray Society (ARRS) and the European Congress of Radiology (ECR) among others. Dr. Merkle is on the editorial board of European Radiology and the Journal of Endovascular Therapy. Dr. Merkle has been invited for numerous lectures, is a visiting professor to universities worldwide, and has published more than 100 peer-reviewed manuscripts and 15 book chapters. About Duke University The Duke University School of Medicine is a community of scholars devoted to understanding the causes, prevention and treatment of human disease. Ranked in the top ten with schools twice its age, Duke is committed to socially relevant education, translational research, compassionate patient care and global healthcare solutions. 1a 1b Patient is a 77-year-old woman with diffuse fatty infiltration of the liver. 3D Dual Echo was used to acquire the transverse T1-weighted opposed-phase (TR/TE 4.3/1.3) (1a) and in-phase (TR/TE 4.3/2.6) (1b) MR images at 3.0T. The image pair shows a marked decrease in the signal intensity of the liver on the opposed-phase image, compared with that on the in-phase image. A GE Healthcare MR publication • Autumn 2007 25 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE ABDOMINAL IMAGING – 3D DUAL ECHO Case 2 Case 3 3a 2a 3b 2b Patient is a 36-year-old woman with diffuse fatty infiltration of the liver, focal nodular hyperplasia in the right hepatic lobe and left-sided adrenal adenoma. (2a) Transverse T1-weighted 3D opposed-phase (TR/TE 4.3/1.3) with 3D Dual Echo and (2b) in-phase ((TR/TE 4.3/2.6) MR images acquired at 3.0T demonstrate a well defined focal liver lesion in the right lobe, which appears hyperintense in comparison to the surrounding hepatic parenchyma on the opposed-phase image and stealth on the in-phase image due to substantial diffuse fatty infiltration. Gadolinium-enhanced series (not shown) demonstrated early arterial enhancement, suggestive of a focal nodular hyperplasia. Note the signal drop in the left adrenal gland on opposed-phase imaging indicative of an adrenal adenoma. Patient is a 49-year-old woman with transfusional hemosiderosis. (3a) Transverse T1-weighted 3D opposed-phase (TR/TE 4.3/1.3) with 3D Dual Echo and (3b) in-phase (TR/TE 4.3/2.6) MR images acquired at 3.0T demonstrate decreased signal intensity in the liver and spleen on the image with the longer echo-time. Note the reversed contrast between the hepatic veins and surrounding liver parenchyma on the image with the longer echo time. This finding can be attributed to substantial iron storage in the liver and spleen causing an accentuated free induction decay due to pronounced T2* effects. Conclusion The 3D Dual Echo sequence marks a significant advancement in body MR imaging at both 1.5T and 3.0T. The benefits include higher SNR with one breath-hold for consistently clear images, a reduction in T2* effects by acquiring first opposed-phase and first in-phase images and an ability to do 3D multiplanar reformatting. As shown by the clinical examples, 3D Dual Echo generates high resolution, volume images that can lead to greater diagnostic confidence. 26 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. GE Healthcare A MR for every facility and every body 3.0T Signa HDx 3.0T Capture detail you couldn’t see before for a definitive diagnosis on every scan. High-performance highdefinition imaging capabilities help you diagnose your most challenging cases. 1.5T Signa HDx 1.5T, Signa HD 1.5, Signa HDe 1.5T Powerful, high-definition MR delivers a more definitive diagnosis and a full compliment of applications. Choose the high performance of our 32-channel Signa HDx or the smaller and simpler Signa HDe that takes up 30% less space. Open Signa OpenSpeed, Signa Ovation, Signa Profile The open concept of our Open MR family helps reduce patient anxiety while the remarkable resolution and high-performance applications give you more access, more image quality and more peace of mind. Service to keep you up and scanning GE technology offers more worldwide support than any other MR available today. We have more service engineers. More application specialists worldwide. More parts distribution centers. You also get more physician training options. Even remote diagnostic and solutions network for real-time, on-line support. The GE Continuum.™ Designed for what’s next. Every GE MR system is designed with the future in mind. That’s the Signa Continuum. Easy upgrades keep your technology current and competitive. And make your investment last. Capturing images you could once only capture in your imagination. MR Re-imagined. MR Guided Focused Ultrasound Treat uterine fibroids non-invasively without an incision. All GE Signa MR systems are exclusively compatible with InSightec™ technology that helps you expand your spectrum of care. ©2007 General Electric Company GE Medical Systems, a General Electric Company doing business as GE Healthcare The information contained in this document is current as of publication of the magazine. CLINICAL VALUE NEURO – PROPELLER HD Efficient Image Quality Enhancements in Temporal Bone Imaging Using PROPELLER HD By Mathieu H. Rodallec, M.D., Senior Radiologist in MRI, Saint-Joseph Hospital Cholesteatoma and Diffusion-weighted Imaging Cholesteatoma is a cystic lesion lined with keratin-producing squamous epithelium filled with desquamation debris in the middle ear. Patients with the disease are treated surgically, but the procedure carries the risk of residual cholesteatoma and tumor recurrence in a relatively high number of patients. CT has a high negative predictive value if no soft-tissue mass is detected. However, if a patient treated surgically has a soft-tissue mass, additional diagnosis with a CT study is not possible because cholesteatoma, granulation tissue and cholesterol granuloma cannot be differentiated from one another on CT. MR imaging of the temporal bone can help in characterizing potential soft-tissue abnormalities shown on CT. Diffusion-weighted MR imaging (DWI) generates valuable information regarding diffusion motion of water protons in biologic tissue. DWI can also help confirm residual or recurrent cholesteatoma in patients who undergo middle ear surgery by showing a high-signalintensity lesion. Other tissues found in the middle ear after surgery demonstrate a low signal intensity on diffusion-weighted MR images. The PROPELLER HD™ sequence from GE Healthcare can be useful to detect recurrent cholesteatoma in patients post middle ear surgery and helps to minimize the numerous susceptibility artifacts that create high signal intensity in the air-bone interfaces or in the posterior fossa. CT examination Figure 1. 28 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. NEUR O – PR OPELLER HD CLINICAL VALUE Clinical Case An 80-year-old female underwent right middle ear surgery for cholesteatoma. A CT image shows a soft-tissue mass in the right middle ear. T1-weighted MR image post-contrast media injection depicts two lesions in the middle ear surgical cavity with peripheral granulation tissue. The DWI sequence demonstrates numerous susceptibility artifacts in the temporal bone. Mathieu H. Rodallec, M.D. Mathieu H. Rodallec, M.D., is a Senior Radiologist in MRI at SaintJoseph Hospital in Paris, France, and board certified in Diagnostic Radiology. He received his medical degree from the School of Medicine of Paris, and fellowship training at Beaujon Hospital of the University of Paris VII. His interests include neuroradiology, head and neck radiology and musculoskeletal imaging. He has published training material, authored publications and abstracts and has given numerous presentations at educational meetings. He is a member of the French Society of Radiology (SFR), French Society of Neuroradiology (SFNR) and Radiological Society of North America (RSNA). Findings Image obtained on the same patient using the PROPELLER HD DWI sequence clearly demonstrates the high-signal intensity cholesteatoma (red arrow) and a cholesterol granuloma (green arrow). Conclusion The PROPELLER HD sequence improves image quality in the vicinity of bone/tissue and air/tissue interfaces that are prone to creating susceptibility artifacts. PROPELLER HD DWI can suppress susceptibility artifacts, particularly helpful in temporal bone imaging to detect residual or recurrent cholesteatoma. PROPELLER diffusion B : 600 s /mm2 Sl. thickness 3.0mm 12 slices Matrix 128X128 Acq. Time 03 :18 8 NVHEAD-A Saint-Joseph Hospital is a 746-bed, private, non-profit public service hospital. In January 2006, Saint Michel Hospital and Notre Dame de Bon Secours Hospital joined Saint-Joseph to form the Paris Saint-Joseph Hospital Group. Today, the three hospitals provide a full range of heath services for patients south of Paris. MR examination Acknowledgements: Case written in collaboration with Souleiman Amoussa, Advanced MR Applications, GE Healthcare, Vélizy, France. Figure 2. T1-weighted post-contrast MR image Figure 3. DWI-EPI Figure 4. PROPELLER HD DWI A GE Healthcare MR publication • Autumn 2007 29 The information contained in this document is current as of publication of the magazine. CLINICAL VALUE CARDIOLOGY – REPORTCARD Validation of an Automated Left Ventricular Segmentation Technique for Quantifying Stroke Volume By Cindy R. Comeau, BS, RT(N)(MR), Parikshit Prasad, Balaji Raman, Kavitha Subramanian and Steven D. Wolff, M.D., PhD This work was presented at the 16th Annual Meeting for the Section for Magnetic Resonance Technologists (SMRT) in Berlin, Germany on May 19-20, 2007, held in conjunction with The International Society for Magnetic Resonance in Medicine (ISMRM) and the European Society for Magnetic Resonance in Medicine and Biology (ESMRMB) Joint Annual Meeting. Purpose Many clinicians consider MRI the imaging test of choice for quantifying left ventricular (LV) end-diastolic volume, endsystolic volume, stroke volume (SV) and ejection fraction (EF). Typically, volumes are derived by segmenting the LV endocardial border on serial short axis images. However, this method presents several clinical challenges. First, as the endocardial contours are of low spatial frequency, papillary muscles and trabeculations are often included in the ventricular cavity. Second, it is difficult to determine 30 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. CARDIOLOGY – REP ORTCARD CLINICAL VALUE About the Authors: the precise position of the LV base due to poor spatial resolution in this dimension (spatial resolution is equal to slice thickness, which is typically around 8 mm). Third, if segmentation is performed manually, the number and location of the endocardial borders is subjective. Cindy R. Comeau, BS, RT (N)(MR) is the Chief Technologist at Advanced Cardiovascular Imaging (New York, NY), a private practice in Manhattan. Steven D. Wolff, M.D., PhD, is the Director of Cardiovascular MRI and CT at Advanced Cardiovascular Imaging. The purpose of this study was to assess whether commercially available software could provide more accurate and more reproducible quantification of LV volumes and ejection fraction. Kavitha Subramanian is the Engineering Director, Balaji Raman, Lead System Designer, and Parikshit Prasad, Image Processing Engineer, at NeoSoft, a software provider that works in close collaboration with GE Healthcare. The company’s principle product is ReportCARD, used to view, analyze and report cardiac MRI studies. Methods LV volumes and ejection fraction were derived using two distinct methodologies. Method 1 (Manual): The subendocardial contours were drawn manually at enddiastole and at end-systole. The cardiac base was determined subjectively, as the most basal slice where myocardial tissue comprised more than 50 percent of the circumference of the blood pool. Method 2 (Semi-automated): LV volumes were determined using the semi-automated analysis in ReportCARD 3.0™ from GE Healthcare. The ReportCARD software produces endocardial borders with high spatial frequency, thereby excluding papillary muscles and trabeculations from the LV cavity. It also determines the basal and apical extent of the LV on short axis images, based on user input of these locations on a 2-chamber long-axis cine. Stroke volumes were calculated using these two methodologies and compared to the aortic flow as assessed from the phase-contrast images. In patients without valvular disease, the LV SV should equal the aortic flow. 50.0 LV Stroke Volume – Aortic Flow (ml) We retrospectively analyzed 20 cardiac MRI studies in patients without valvular disease, performed on a GE Healthcare Signa®1.5T HDx scanner. All MRI studies included a series of contiguous, prospectively ECG gated short-axis cines through the left ventricle and a 2-chamber long-axis cine (FIESTA pulse sequence: TR/TE,3.1/1.4, BW=125, matrix=192x160 FOV=35-38, views-per-segment=24, 20 reconstructed phases per cardiac cycle). Prospectively ECG gated phase contrast images of the aorta were acquired at the aortic root 1-2 cm distal to the aortic valve (TR/TE, 7.2/2.9, BW=31, matrix= 256x128, field-of-view=35-40, views per segment=8, 30 reconstructed phases per cardiac cycle). 40.0 30.0 20.0 10.0 0.0 -10.0 -20.0 Manual Semi-Auto -30.0 Figure 1 Results Conclusion The semi-automated method of ReportCARD gives a more accurate measurement of SV, based on better concordance of SV with aortic flow. This is most likely because of more accurate endocardial segmentation and better assessment of the precise location of the LV base. The semi-automated method also yields higher EFs, indicating that manual tracing underestimates the true EF. 90% 80% Ejection Fraction (EF) The difference between LV SV and aortic flow was 10 + 15 ml using manual traces and 0 + 10 ml using the semi-automated method of ReportCARD (mean + standard deviation; p<0.02). The difference between LV SV and aortic flow for each method was determined (Figure 1). The average EF was 56 + 11 percent using the manual method and 66 + 12 percent using the semi-automated method of ReportCard (P <0.01) (Figure 2). 100% 70% 60% 50% 40% 30% 20% 10% Manual Semi-Auto 0% Figure 2 A GE Healthcare MR publication • Autumn 2007 31 The information contained in this document is current as of publication of the magazine. T E C H N I C A L I N N O VAT I O N HIGH DEFINITION MR – SIGNA HDXT Re-Defining the Next Generation of High Definition Current challenges in MR imaging include obscured pathologies, inconsistent imaging and variable exam times. The introduction of Signa® HDxt culminates years of GE Healthcare research and development on High Definition (HD) MR imaging. Today, the need for imaging technology for specific exams is paramount to assist with imaging pathologies that were once thought to be too complex, produced inconsistent image outcomes and extended the exam time. Grounded in the development of HD MR is technology specifically designed for each anatomical exam that will help maximize imaging accuracy, consistency and efficiency. This integrated technology for anatomically specific coils, pulse sequence applications and patient table complete the GE HD MR imaging chain. Signa HDxt extends the concept of HD to gapless 3D imaging for early lesion detection and high-resolution imaging techniques for minimizing image variation for consistent high quality outcomes. Signa HDxt delivers MR imaging essentials for a more confident diagnosis. Clinicians want high quality imaging with increased signal-to-noise ratio (SNR), high resolution and no artifacts. To compare images, they require the same anatomy in the exact same position in each slice, with specific and known parameter differences between the images so that unexpected changes can be easily seen. Multiple image contrast is crucial for clinicians to differentiate between tissues. Along with Signa HDxt, GE introduces the next generation in high definition imaging with a series of HD pulse sequence applications, reporting tools, surface coils and host software improvements. 32 A GE Healthcare MR publication • Autumn 2007 New High-density Clinical Applications and Ease of Use Enhancements With Signa HDxt MR, clinicians have the tools for reliable, reproducible detection of very small lesions with sub-millimeter spatial resolution, consistent HD image quality providing excellent tissue contrast with automated and intelligent protocols and a single 3D volume acquisition that replaces today’s plane-after-plane or slice-by-slice acquisitions, reducing the number of scans and total exam time. The new applications that are changing the paradigm of MR imaging include: • Cube™, a volumetric fast spin echo (FSE) imaging sequence • 3D Dual Echo, a 3D FSPGR sequence that produces fat/water in-phase and opposed-phase images in a single breath hold • IDEAL, an innovative method for fat and water suppression • ARC, a data-driven parallel imaging method Host enhancements further simplify the exam, saving time. A selectable auto-transfer capability allows flexibility of image series data transfer. Auto-contrast copies contrast designation to the appropriate series in the prescription. GRx enhancements include reverse order slice numbering for visual preference, which saves the localizer image for easy prescription reference, and Copy Shim Volume that streamlines time in managing the prescription. An auto-voice enhancement adjusts voice speed for clear patient comprehension. The information contained in this document is current as of publication of the magazine. HIGH DEFINITION MR – SIGNA HDXT Knee Array Cardiac Array T E C H N I C A L I N N O VAT I O N Neurovascular Array New Intelligent Reporting Tools Signa HDxt addresses the need for greater efficiency in radiology reporting with the release of new tools on Advantage Workstation: • BrainSTAT with diffusion imaging for an effective way to assess and quantify blood circulation dynamics in brain tissue • ReportCARD 4.0, a structured reporting tool with macros and a research database added to the functionality of post processing for cardiac imaging, to further reduce the amount of time a clinician spends reporting a cardiac MRI case • Flow Analysis Tool extends functionality to include multiple regions of interest (ROI) and ease-of-use enhancements, reducing the amount of time a clinician spends reporting a cardiac MRI case • Vascular Reporting Tool, a research database that allows searching for cases with specific pathology for faster report generation than with standard voice dictation • Multi-Echo Signal Analysis & Reporting Tool produces grayscale and color maps depicting the iron concentration estimation based on user provided input scaling New High-density Coils Complete the Image An integral piece of the HDxt release is the introduction of new high-density surface coils for orthopedic imaging with 1.5T and 3.0T systems. These surface coils provide improved SNR, coverage and parallel imaging support for shoulder, wrist and foot and ankle exams. GE’s new 8-channel shoulder coil utilizes a concentric coil design that provides 30 percent improvement in coverage Breast Array Torso Array while advancing SNR penetration over previous designs. This proprietary coil technology enables the use of parallel imaging in any plane. Designed to help minimize patient motion during an exam, the flexible coil housing accommodates both large and small patients. For high-resolution foot and ankle imaging, the new 8-channel foot/ankle coil incorporates a novel “ski” boot design for simple and reliable patient setup. This design permits imaging of the foot in either a vertical or 15 degree or less plantar flexed orientation with 5-degree increments. The element layout supports a 20 cm FOV and is optimized for parallel imaging in any plane. The SNR of this design supports the high-resolution clinical requirements for visualizing small structures and abnormalities common in MSK imaging. At 3.0T, a new 8-channel wrist coil provides easy patient set up and allows positioning by the patient’s side or directly above them. The coil locks firmly into a stabilized base-plate to reduce motion artifact. With a 12 cm FOV optimized for parallel imaging, the 8 channel wrist coil produces exquisite images of structures. A ContinuumPak™ for HDx Users Signa HDx users will realize the benefits of the GE Continuum™ with the HDxt ContinuumPak, which upon release will be installed via the user’s local GE applications field engineer. The HDxt ContinuumPak includes new HD applications such as 3D Dual Echo, Advantage Workstation reporting tools BrainSTAT, Flow Analysis and Vascular Reporting and host software enhancements. The HDxt ContinuumPak further enhances GE Healthcare’s commitment to users by delivering the next generation of HD MR images. Head-NeckSpine Array A GE Healthcare MR publication • Autumn 2007 33 The information contained in this document is current as of publication of the magazine. T E C H N I C A L I N N O VAT I O N N E U R O A N D M U S C U LO S K E L E TA L – C U B E 3D FSE Reduces Scan Time, Generates Thinner Slices Clinicians can view smaller lesions with greater confidence By Reed Busse, PhD, Senior Scientist, GE Healthcare In fast spin echo sequences, scan time can be reduced by increasing the Echo Train Length (ETL). If the ETL is too long, however, signal decay results in a disappointing blurring of the images. Today, this challenge is resolved with a new, unique method developed by GE Healthcare to modulate the refocusing flip angles, called Cube™, which extends and reshapes the signal decay curve. Cube is a single-slab 3D FSE imaging sequence only available on GE’s Signa® HDxt 1.5T and 3.0T platforms. When refocusing flip angles that are less than 180° are used, natural equilibrium exists between encoded longitudinal and transverse magnetization, which is a function of the refocusing flip angle. Cube utilizes this powerful phenomenon, modulating the refocusing flip angle to drive this equilibrium. At the beginning of the echo train, flip angles are rapidly reduced to store excess magnetization in an encoded longitudinal state. By increasing the flip angle, this sequence converts the slowly decaying longitudinal magnetization back to transverse magnetization to provide signal over a much longer train. These advantages are compounded by advances in parallel imaging – simultaneous acceleration in two directions with GE’s innovative auto-calibrating data-driven parallel imaging method, ARC*. Very large 3D data matrices may now be acquired in relatively few echo trains, revolutionizing T2-weighted imaging. The large increase in efficiency allows additional and thinner slices to be acquired, producing voxels that are no larger in the slice direction than in-plane. With this isotropic resolution, the plane of acquisition becomes immaterial – as the volume is prescribed in a manner that yields the high image quality and efficiency. Images are reconstructed in axial, sagittal and coronal planes, or any oblique orientation, from a single short acquisition. Cube removes prior limitations that result in a small number of relatively thick sections, giving clinicians new capabilities to acquire wide anatomic coverage in a high-resolution 3D dataset. Figure 1B Flip (degrees) Percent proton density signal Figure 1A RF pulse Echo Figure 1A: A modulated flip angle refocusing train of RF pulses establishes a low-angle pseudo-steady state, and then increasing throughout the remainder of the train. Figure 1B: This serves to decouple much of the signal modulation from the development of contrast. Signals from tissues with different T2 values diverge, producing contrast, while remaining relatively constant, producing sharp images with the highly efficient Cube acquisition. *ARC: Autocalibrating Reconstruction for Cartesian imaging 34 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. N E U R O A N D M U S C U LO S K E L E TA L – C U B E T E C H N I C A L I N N O VAT I O N This highly efficient technique enables Cube to join the ranks of GE’s other rapid 3D volumetric sequences, and complement them by providing important contrast options, such as T2, T2-FLAIR and PD. While it has the potential of being applied to a wide range of anatomic areas, Cube is initially intended for Neuro and MSK applications. When used in conjunction with GE’s other 3D applications, Cube may allow technologists to perform a complete MR study in a 3D acquisition mode. Reed Busse, PhD Benefits of Cube With a single acquisition, the radiologist can visualize the entire data set in axial, sagittal, coronal and any oblique orientation. The need for image retakes due to missing slices or planes is minimized and submillimeter voxels may help clinicians detect small 2-3 mm lesions. Automated protocols optimize sequences for clinical use, facilitating ease-of-use and consistency across imaging studies. Cube is convenient for patients with less SAR than conventional FSE. Figure 2 Reed Busse, PhD is a Senior Scientist at the GE Healthcare Applied Science Lab at the University of Wisconsin, Madison. As a lead innovator at GE, Dr. Busse holds five patents and five patents pending for his developments in MR imaging. He received his doctorate degree in Biomedical Sciences from Mayo Graduate School and a B.A. in Physics, with magna cum laude distinction, from Carleton College. Dr. Busse is a member of the International Society for Magnetic Resonance in Medicine and American Association of Physicists in Medicine. Figure 3 Whole knee imaging with 0.6mm isotropic resolution in 4min 40sec. (Courtesy Dr. Garry Gold, Stanford University) Figure 4 Whole Brain Imaging. T2-weighted 3D-FR Cube (a) and CSF-nulled 3D-FLAIR Cube (b) complement T1-weighted 3D-IR-SPGR (c) to provide a whole brain exam in just 10 minutes (2:15 for the T2 Cube, 5:00 for the FLAIR Cube, 2:45 for the T1-IR-SPGR). Acquisition matrix of 256x256x128 (zipped to 512x512x256). (Courtesy Dr. Howard Rowley, University of Wisconsin, Madison) T2-weighted volumetric imaging for evaluation of uterine anomalies with 3D-Cube. (Courtesy Dr. Elizabeth Sadowski, University of Wisconsin, Madison) A GE Healthcare MR publication • Autumn 2007 35 The information contained in this document is current as of publication of the magazine. T E C H N I C A L I N N O VAT I O N PARALLEL IMAGING – AR C New Parallel Imaging Method Enhances Imaging Speed and Accuracy Enables Fast, Robust Scanning Even with Motion or Tight FOV Prescription By Anja Brau, PhD, Senior Scientist, GE Healthcare, Global Applied Science Lab Over the last decade, parallel imaging technology in MRI has progressed from early research prototype to established clinical tool. By exploiting the spatial arrangement of phasedarray receiver coils, parallel imaging can accelerate MR data acquisition, which in turn can reduce scan time and improve diagnostic utility. Figure 1 External calibration. There are two basic classes of parallel imaging methods. “Physically-based” methods, such as SENSE,1 require an explicit coil sensitivity map to model the underlying physical process that occurs during image acquisition. The success of physically-based methods relies on calculating accurate coil sensitivity maps, which can be difficult to achieve in practice. Coil sensitivity calibration can be performed in one of two ways: External calibration requires a separate calibration scan (Figure 1). However, a primary source of error in this case is motion that can occur between the calibration scan and the accelerated scan – for example, due to different breath-hold positions – causing residual aliasing artifacts in the final image due to a mismapping of coil sensitivities. Internal calibration embeds a small amount of calibration data within the accelerated scan itself (Figure 2). While this approach is more robust to motion, a primary source of error is insufficient resolution, especially when a tight field of view (FOV) is prescribed. 36 A GE Healthcare MR publication • Autumn 2007 Figure 2 Internal calibration. The information contained in this document is current as of publication of the magazine. PARALLEL IMAGING – AR C T E C H N I C A L I N N O VAT I O N What makes ARC unique? ARC’s unique 3D kernel fully utilizes available data along ALL three directions, unlike other methods that only use 1D kernels. A 3D kernel means more accurate reconstructions and improved image quality. Only GE’s efficient, streamlined ARC reconstruction can leverage the power of a 3D kernel. Figure 3 “Data-driven” methods, such as GRAPPA2, comprise the second class of parallel imaging techniques. These methods do not require an explicit coil sensitivity map but rather rely on “training” data to calibrate the reconstruction directly, thus avoiding errors from coil sensitivity mismapping. Furthermore, the training data is typically embedded in the acquisition in an autocalibrated manner, minimizing the susceptibility to motion errors. ARC: A Step Forward for Parallel Imaging GE has developed a new data-driven parallel imaging reconstruction known as ARC, or Autocalibrating Reconstruction for Cartesian imaging, that represents a major step forward in the speed and accuracy of highly accelerated parallel imaging. Unlike other methods,2,3 ARC uses a full 3D kernel to synthesize missing target data (Figure 3, shown in pink) from neighboring source data (Figure 3, shown in green) from all three imaging directions. In this way, ARC’s 3D kernel takes full advantage of available information along all three dimensions for improved reconstruction accuracy with fewer required calibration lines. The end result is highly accelerated MR data acquisition with improved image quality and fewer artifacts. Anja Brau, PhD Anja Brau, PhD, is a Senior Scientist with GE Healthcare’s Global Applied Science Lab in Menlo Park, CA. Anja specializes in the development and clinical validation of innovative MR acquisition and reconstruction techniques for body imaging applications. She is the author of several journal articles, abstracts, and patents and is a member of the International Society of Magnetic Resonance in Medicine (ISMRM). Prior to joining GE, Anja received an undergraduate degree in electrical engineering from Princeton University and a doctoral degree in biomedical engineering from Duke University. The calculation of a full 3D kernel reconstruction, previously considered a computationally prohibitive task, is now feasible with ARC’s streamlined reconstruction. Several innovations in the calculation of the training and synthesis phases allow ARC to reduce computation time.4,5 For example, while ARC’s training phase is performed in k-space (kx, ky, kz), the synthesis phase is performed in hybrid (x, ky, kz) space (Figure 4) following 1D Fourier Transformation along kx, reducing the 3D kernel neighborhood to a smaller, more manageable 2D kernel neighborhood. These strategies drive the computational efficiencies that streamline ARC reconstruction, creating new possibilities such as the ability to compute a 3D kernel in clinically practical reconstruction times. ARC enables highly accelerated parallel imaging with an accurate, streamlined reconstruction. Because it is autocalibrating and requires no coil sensitivity map, ARC enables smaller FOV prescriptions and is less sensitive to motion artifacts compared to conventional parallel imaging techniques. ARC can potentially replace physically based methods that can suffer from image artifacts caused by inaccuracies in coil sensitivity calibration. In clinical testing, the technique used by ARC has been shown to achieve high quality reconstructions even in challenging imaging applications, such as tight FOV prescription. A GE Healthcare MR publication • Autumn 2007 37 The information contained in this document is current as of publication of the magazine. T E C H N I C A L I N N O VAT I O N PARALLEL IMAGING – AR C ARC reconstruction phases Synthesis Training Figure 4 2D kernel 3D kernel ARC training phase is performed as a 3D kernel in k-space, whereas the synthesis phase is performed as a 2D kernel is hybrid (x, ky, kz) space, reducing computation time. Benefits Patients may experience shorter exam times and a lower likelihood for repeat scans due to error or poor image quality. Ease of use and less opportunity for error typically enables the technologist to produce more consistent scans that are less sensitive to prescription errors. Referring physicians are likely to receive more definitive reports with better image quality. ARC is available on the Signa® HDxt platform for use in conjunction with GE’s signature volumetric imaging application Cube™. 38 A GE Healthcare MR publication • Autumn 2007 Courtesy of Lawrence N. Tanenbaum, MD, Edison Imaging. With ARC, clinicians can expect improved image quality and patient throughput, increased spatial resolution or volumetric coverage, depending on the application. Imaging FOV can be prescribed close to or even smaller than the anatomy of interest, enabling higher spatial resolution and diagnostic confidence. ARC’s reliability for tight FOV prescription allows the technologist greater tolerances for FOV placement which can reduce the opportunity for error. Autocalibration improves workflow and further reduces the opportunity for error, making the scanning process easier for the operator. ARC is robust against motion, reducing residual aliasing artifacts that would otherwise result from a mismatch between the calibration and accelerated scan. 1mm lesions with Cube on Signa 3.0T. References 1. Pruessmann et al. MRM(42):952-962,1999. 2. Griswold et al. MRM 47(6):1202-10,2002. 3. Blaimer et al. MRM 56(6),1359-64,2006. 4. Beatty et al. p.1749. Proceedings of the ISMRM, 2007. 5. Brau et al. p.2462. Proceedings of the ISMRM, 2006. The information contained in this document is current as of publication of the magazine. N E U R O L O G Y – B R A I N S TAT Quantitative Tool for Neurological Brain Evaluation Mental and neurological disorders affect an estimated 450 million people worldwide, and account for approximately 13 percent of disability-adjusted life years, or DALYs, a measure of the amount of health lost as a result of a particular condition or disease.1 Disorders such as Alzheimer’s, Parkinson’s, epilepsy, dementia and stroke pose a growing health problem for nearly all countries. In the U.S. alone, stroke is the third leading cause of death, claiming one in 16 lives according to the American Stroke Association. Of the 700,000 people who experience a stroke each year, 500,000 are sufferers of a first attack and 200,000 experience recurrent attacks. In addition, 87 percent of all strokes are ischemic, whereas intracerebral and subarachnoid hemorrhage strokes make up the remaining 13 percent.2 T E C H N I C A L I N N O VAT I O N CBF quantifies the volume of arterial blood (ml) delivered to 100mg of tissue per minute, thus representing instantaneous capillary flow in tissue. CBV describes the blood volume of the cerebral capillaries and venules (not arteries) per cerebral tissue volume. MTT measures the length of time a certain volume of blood spends in the cerebral capillary circulation. TTP is inversely related to CBF in which reduction of blood flow results in an increase in the time needed for the contrast to reach its peak in the perfused volume of brain tissue. In spite of the acute stroke being a leading cause of serious, long-term illness, many patients are not diagnosed correctly or the diagnose arrives too late for the ischemic stroke patients to benefit from tPA (thrombolysis) treatment, which has to be administered within three hours of the onset of the disease. Therefore, the need to quickly diagnose and correctly differentiate stroke is an important driver in neurological imaging today. MR offers excellent clinical properties for imaging neurological conditions, such as stroke, allows complete assessment in a single exam, and assists physicians in making a differential diagnosis. To address the growing need for sophisticated neurological imaging, BrainSTAT is a new advanced post-processing tool from GE Healthcare that allows quantitative evaluation of neurological conditions, as well as helps visualize vascular structure and flow in the tissue surrounding brain lesions. As a result, clinicians may use it to more precisely diagnose the extent and severity of ischemic brain disease, and better tailor an individualized therapy plan. CBF (ml/100mg/min) CBV (ml/100mg) MTT (sec) These parametric images reflect the spatial distribution of blood flow, blood volume per 100 mg of tissue, and the time it takes for blood to perfuse through the tissue being imaged. Designed for the new Signa® HDxt MR, BrainSTAT calculates regional cerebral blood flow (rCBF), blood volume (rCBV), mean transit time (rMTT) and time to peak (TTP) for every pixel from a time series of MR image data. The results are visualized as color-coded maps. Based on the widely accepted, scientifically proven Gamma Variate Fit algorithm, BrainSTAT provides objective and reproducible data on pathologies that may assist clinicians in delivering better, more personalized care. References 1. Mental and Neurological Disorders. July 2006 newsletter by the Disease Control Priorities Project. Available at: http://www.dcp2.org/file/60/DCPP-Mental%20Health.pdf 2. American Heart Association/American Stroke Association. Heart Disease and Stroke Statistics – 2007 Update. Available at: www.americanheart.org A GE Healthcare MR publication • Autumn 2007 39 The information contained in this document is current as of publication of the magazine. T E C H N I C A L I N N O VAT I O N 1.5T MRI – SIGNA HDE Enhancements Bring Sophisticated MR Applications Within the Reach of Everyone 40 A GE Healthcare MR publication • Autumn 2007 The information contained in this document is current as of publication of the magazine. 1.5T MRI – SIGNA HDE T E C H N I C A L I N N O VAT I O N The HDe Value Proposition In today’s healthcare market, radiologists want accurate and reliable diagnostic imaging that can lead to a confident diagnosis. Yet, today’s competitive reimbursement environment, and, in particular, reductions that resulted from the Deficit Reduction Act (DRA) of 2005, necessitate a cost-conscious environment. GE Healthcare continues its commitment to an upgrade continuum path with Signa HDe. As a facility’s diagnostic imaging needs evolve, so too can the Signa HDe. GE’s MR continuum path enables users to completely upgrade their system to the industry-leading HDx platform and today’s most advanced clinical applications. The Signa® HDe 1.5T MR system answers this challenge by delivering excellent clinical performance that meets a facility’s purchasing needs. With over 200 worldwide installations, Signa HDe brings the clinical advantages of MR technology to a broader population base by addressing the challenges of space, cost and ease of use. Plus, signature HD applications such as the GE-exclusive LAVA™, TRICKS™, PROPELLER HD™ and VIBRANT® sequences give users state-of-the-art MR capabilities. Signa HDe fits where other 1.5T MR systems can’t. The system can be sited with 30 percent less space and on average generates 25 percent less operating cost than a traditional 1.5T MR system, which translates to facilities recouping their investment with as few as five billable patients each day. Building on this success, GE Healthcare now offers additional capability on the Signa HDe for increased operational efficiency and investment protection. New applications enable increased clinical benefits for Signa HDe users, including: • PROBE for proton brain spectroscopy • Cartilage visualization using color-coded mapping with Cartigram™ • Improved gray-white matter imaging contrast and lesion visualization on cervical spine images with MERGE The system boasts a user-friendly interface and a full range of High-definition (HD) coils for head-to-toe anatomical coverage. Together, these enhancements to Signa HDe provide the radiologist and technologist with additional capabilities to generate clear, accurate and complete images in key areas. Without PROPELLER HD With PROPELLER HD A GE Healthcare MR publication • Autumn 2007 41 The information contained in this document is current as of publication of the magazine. T E C H N I C A L I N N O VAT I O N ANGIOGRAPHY – NON CONTRAST ENHANCED PULSE SEQUENCES Robust NCE Techniques Remain a Viable Alternative for MR Angiography By Stuart Clarkson, Americas MR Training Manager, GE Healthcare Non contrast enhanced magnetic resonance angiography (NCE-MRA) has become a global topic of interest following the recent link between nephrogenic systemic fibrosis (NSF) and gadolinium contrast agents.1 Reports2 dating to the year 2000 identify a scleromyxoedema-like cutaneous disease in renal-dialysis patients that may well have been associated with gadolinium; however, the link between NSF and MR contrast agents had yet to be made. Gadolinium-based contrast agents are used in many MR examinations, but its use has it been of particular interest in NSF due to the larger doses of contrast required for cardiovascular imaging compared to MR examinations of other anatomy. Additionally, patients who receive an MRA of the renal arteries may have been at additional risk of NSF due to renal impairment. NCE Techniques GE Healthcare’s Signa® HDx and HDe systems incorporate no less than 10 pulse sequences capable of imaging the vasculature without the use of a contrast agent. These include: 1. 2D Phase Contrast 2. 3D Phase Contrast 3. CINE Phase Contrast 4. 2D Time of Flight (gated and non gated) 5. 3D Time of Flight (includes MOTSA) 6. 2D fat sat FIESTA 7. 3D fat sat FIESTA 8. 3D FSE (black blood angio) 9. 2D Double Inversion Recovery 10. MR Echo* (FIESTA based real time sequence on HDx 1.5T) The Clinical Impact Many institutions implemented a policy of screening patients scheduled for a contrast enhanced MR imaging study to ensure adequate renal function prior to the administration of a gadolinium-based agent. If the patient exhibits impaired renal function that prevents the institution from performing an intravenous injection of a gadolinium agent, then non-contrast imaging is utilized. Imaging renally-impaired patients without a contrast agent presents a challenge when visualization of vascular structures is required. The imaging challenge in assessing vascular anatomy without a contrast injection is deciding which sequence to use for interrogating the vascular anatomy of interest. As with all MR imaging sequences, there is a perpetual trade-off between resolution and scan time for obtaining the adequate signal-to-noise-ratio (SNR) in an image. With MRA, there is the additional consideration of blood flow when selecting the appropriate sequence. 3D Time of Flight (ToF) sequences (Figure 1) exhibit excellent spatial resolution; however, due to saturation effects and subsequent loss of signal, these are seldom used in slow Portal Vein Figure 1. 3D ToF 42 A GE Healthcare MR publication • Autumn 2007 Figure 2. Gated 2D ToF Figure 3. 2D FIESTA MiP The information contained in this document is current as of publication of the magazine. ANGIOGRAPHY – NON CONTRAST ENHANCED PULSE SEQUENCES flow areas. 2D ToF techniques (Figure 2) may be utilized when imaging long vessels that have slower flow rates. In pulsatile vessels, the sequence should be gated to the patient’s heart rate to mitigate artifacts. Steady-state free precession sequences such as FIESTA (Figure 3) are excellent for fast scans done in a breath hold. When targeted to specific vascular anatomy, high in-plane resolution is easily achievable. Phase contrast techniques provide excellent background subtraction resulting in 3D volumes (Figure 4) that are easily rotated into any viewing plane. 3D phase contrast techniques are significantly slower that the breath hold times seen with contrast enhanced techniques; however, when combined with a CINE acquisition, the phase contrast techniques are capable of quantifying flow in any vessel. T E C H N I C A L I N N O VAT I O N “For our non-contrast MRA studies, we generally rely on two complimentary techniques: 2D Time of Flight (to obtain images with venous suppression) and Steady-State Free Precession (i.e. FIESTA), that has very few flow artifacts. However, today most MRA studies are performed with sequences like eFGRE or using multi-phase, time-resolved techniques (e.g. TRICKS), which are very accurate and provide high diagnostic confidence. An additional advantage of these techniques is that one can also assess the dynamics of blood flow. This can be especially helpful in patients with shunts, fistulas or vascular malformations.” Steven Wolff, M.D., PhD, Director of Cardiovascular MRI, Advanced Cardiovascular Imaging, New York, NY Phase contrast techniques are also sensitive to the flow direction of the blood – any flow from Left, Inferior or Posterior is shown as black and flow from Right, Superior and Anterior shown as white. Flow within the right middle cerebral artery (Figure 5) is from the left to the right and hence is black on the phase image. Also note that 3.122 mLs of blood passes through this vessel with each heart beat; multiplying this by the patient’s heart rate (55 beats/min) generates the vessel flow rate at 171 mLs/min. Figure 4. 3D Phase Contrast Future Pulse Sequences Despite the comprehensive suite of non-contrast MRA sequences, GE Healthcare continues to evaluate improved techniques for imaging vascular structures without a gadolinium injection. FIESTA-based sequences that utilize various tissue preparation pulses are very promising in their ability to depict vascular structures in various anatomical locations. Figure 5. CINE Phase Contrast of middle cerebral artery and resulting flow measurements. Peak Positive Velocity (cm/s) 83.1 Peak Negative Velocity (cm/s) -6.07 Avg. flow (ml/beat) 3.122 Avg. Positive Flow (ml/beat) 3.158 Avg. Negative Flow (ml/beat) -0.036 Summary MR provides robust visualization of vascular anatomy. In the subset of patients that are deemed unsuitable for a contrast injection, it is reassuring that many techniques exist on the Signa HDx and HDe scanners to image vascular anatomy and quantify flow. These techniques may prolong the exam time, but can be used to achieve the imaging goal. References: 1. Thomsen HS. Nephrogenic systemic fibrosis: a serious late adverse reaction to gadodiamide. Eur Radiol. Epub October 24, 2006 2. Cowper SE, Robin HS, Steinberg SM, Su LD, Gupta S, LeBoit PE. Scleromyxoedema-like cutaneous disease in renal-dialysis patients. The Lancet 356(9234), 16 September 2000, 1000-1 A GE Healthcare MR publication • Autumn 2007 43 The information contained in this document is current as of publication of the magazine. BEYOND THE SCAN FUNCTIONAL MRI – BRAINWAVE AND FIBERTRAK Advanced fMRI Techniques Provide Valuable Information, Change Course of Treatment for Neurosurgical Patients The Methodist University Hospital Neuroscience Institute, in collaboration with the University of Tennessee Health Science Center, provides neuroscience clinical programs, medical education and research that are comprehensive and interdisciplinary. Backed by the latest technologies, including a GE Signa® HD 3.0T MR, the Institute showcases advanced neurology applications, including functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) – both powerful tools that help in planning treatment in patients with brain tumors. fMRI and DTI help physicians identify areas of the brain that affect a patient’s ability to function, (i.e., speech, hearing, vision, muscle control) and therefore must not be disturbed during surgery. fMRI also detects changes in the MR signal that are coupled to changes in neuronal activity. An fMRI scan can produce high-quality images that indicate which areas of the brain are being activated by diverse stimuli. In contrast, DTI is used to examine the wiring of the organized regions of the brain, mapping, the orientation of diffusion along white matter tracts and helping physicians visualize neural pathways. Immediate Benefits Soon after the Signa HD 3.0T system was installed in November 2006, Frank Parks, M.D., Chairman of Radiology for Methodist Healthcare noticed an immediate impact on patient care. Of the first 215 patients scanned using fMRI and DTI, the results changed the course of treatment in 70 cases. “In some of those patients, it has made a very dramatic difference, such as the differences between no surgery versus surgery, or vice versa,” Dr. Parks said. “It has also made a difference in the quality of patient outcomes and the speed of recovery. “In my years in radiology, I’ve seen many new technologies, but I am surprised at the immediacy of impact in this case,” he continued. “It’s not every day we see a technology that directly impacts patient care so quickly after implementation.” fMRI activation areas are co-registered with 3D datasets for custom visualization. 44 A GE Healthcare MR publication • Autumn 2007 The technology has helped the staff at Methodist provide better options for patients with tumors considered unresectable or inoperable. “In such cases, somebody had looked at an MRI and said, ‘That must be functional tissue,’” said Allen Sills, M.D., The information contained in this document is current as of publication of the magazine. FUNCTIONAL MRI – BRAINWAVE AND FIBERTRAK BEYOND THE SCAN Associate Professor of Neurosurgery at the University of Tennessee and medical Director of the Methodist University Hospital Neuroscience Institute. “As it turns out, many times that estimation is just wrong. We’ve been able to use fMRI to show ourselves that indeed we can probably take the tumor out without excessive risk.” The technology’s immediate impact on patient cases soon won over some skeptics. “At first, some neurosurgeons said they were not interested,” Dr. Parks recalled. “A few who have seen the results now say, ‘I want to get my patients scanned.’” Changing Treatments Create DTI 3D fiber maps with GE FiberTrak. In case after case, fMRI/DTI scanning non-invasively provides crucial information that helps surgeons like Dr. Sills make informed decisions on: • Reviewing surgical approach and in choosing the safest path, based on the location of functional brain tissue • Deciding on Operability • Tracking white-matter tracts Choosing the Safest Path The first patient scanned at the Methodist University Hospital with fMRI/DTI was a 20-year-old woman with a right brain tumor diagnosed by MR at another hospital. The team integrated fMRI and DTI with acquisition of 3D anatomical images for the patient’s scheduled image-guided surgery. Clinicians located the tumor in the eloquent cortex near the patient’s motor strip. “It was in an area where we knew the surgery would be delicate,” said Dr. Sills. “We had identified one particular trajectory to the tumor, based on what we believed to be the safer corridor. When we did the fMRI, much to our surprise we found that functional tissue – the tissue that controlled her leg movement – would have been right in the middle of what we had considered our corridor. “There is really no substitute for the real-time, exact, precise information you get from studies like (fMRI and DTI).” Dr. Allen Sills “The information definitely caused me to change my approach and come in by a different route that would be much safer. The patient had been adamant on the front end that she didn’t want any motor deficit, and we were able to accomplish that for her.” A post-operative physical exam found no evidence of foot or ankle weakness. Deciding on Operability In another case, a 51-year-old man was diagnosed with anaplastic astrosarcoma affecting the temporal lobe. Surgeons needed to determine whether the tumor could be resected without significant loss of function. Using fMRI and DTI scanning, clinicians found the area of concern was already disrupted by the tumor, causing the neurosurgeon to proceed with the surgery. “The tumor had been well worked up in previous MR images,” explained Dr. Parks. “The additional information from fMRI and fiber tracking was the tipping point for go or no go.” A GE Healthcare MR publication • Autumn 2007 45 The information contained in this document is current as of publication of the magazine. BEYOND THE SCAN FUNCTIONAL MRI – BRAINWAVE AND FIBERTRAK Another patient, a 38-year-old man, had three areas of brain tumor, including a large growth at the back of the brain near his vision area. Clinicians suspected the lesions were benign, but to remove the large tumor would involve significant resection. “We used fMRI to localize his visual function and were able to see that we could in fact go in and take out that very large lesion – at least 8 cm in size – and not put the patient’s vision at risk,” Dr. Sills said. “It gave us confidence preoperatively that while the risk wasn’t zero, the risk was certainly low that we would cause harm to his vision.” Tracking White-Matter Fibers Another beneficiary of fMRI and DTI was a 22-year-old woman who had a right temporal tumor. “She was left-handed, so the assumption was that her language function must be in the right temporal area,” explained Dr. Sills. “Obviously, there was a great deal of trepidation about approaching this lesion. “It looked like a benign lesion, but she was having seizures and didn’t like being on seizure medicines. She wanted to have the lesion taken out if she could. Our concern was, can we do that safely? fMRI was very helpful. It showed that she had language function in both hemispheres, rather than just one, and that language function area was not anywhere near the lesion. 22-year-old female with right temporal lesion. 2D color directional image (top) shows the displaced white matter. The fMRI image (bottom) demonstrates activation from speech and passive listening paradigms. “In the end, the (DTI) exam gave us two critical pieces of information. First, it helped us decide whether we could even think about surgery. Second, it helped determine our surgical approach.” Dr. Frank Parks 46 A GE Healthcare MR publication • Autumn 2007 “The DTI was incredibly useful because it showed beautifully that the fibers were displaced laterally by the tumor, rather than being infiltrated by it,” he continued. “Without DTI, we would have had no way of knowing that with any degree of certainly. In the end, the exam gave us two critical pieces of information. First, it helped us decide whether we could even think about surgery. Second, it helped determine our surgical approach.” Parks added that the fMRI/DTI findings enabled clinicians to avoid performing an invasive Wada test to locate the speech center. Surgery went forward, and the woman’s speech was not affected. Clinical Value Added The addition of fMRI and DTI was a natural one for Methodist University Hospital, a consistent state leader for brain tumor cases. “At the time we made the investment, it appeared these technologies had moved out of the research lab and had reached the point of being clinically relevant,” Dr. Parks recalled. “We saw them as consistent with our belief in individualized care. They provide information we can use to customize therapy based on the patient’s exact anatomy and pathology.” Clinicians at Methodist scan many brain tumor patients on the Signa® HD 3.0T scanner with fMRI and DTI before craniotomy. Hospital leaders believe the decision to move up to a high-field 3.0T system benefits both clinicians and patients. In addition, Parks has found the procedures easier and the results more reproducible on the Signa HD 3.0T system than on the hospital’s other MR scanners. Technologists use the BrainWave and DTI/FiberTrak suite of applications from GE Healthcare, which offer comprehensive, easy-to-use tools to acquire and The information contained in this document is current as of publication of the magazine. FUNCTIONAL MRI – BRAINWAVE AND FIBERTRAK BEYOND THE SCAN About Methodist University Hospital post-process high-definition 3D anatomical images, neurofunctional brain maps and white-matter trajectories projection. During the procedures, the technologists scan brain anatomy, run the patient through a series of brain stimulations called paradigms that are necessary to perform an fMRI exam, generate DTI images, integrate and post-process the data. The study results are provided to the physicians as 3D, color-coded data sets that can be easily manipulated to best visualize areas of interest. The physicians can study the 3D datasets as part of surgery planning and display the images in the operating room, integrating them with the surgical navigation system. Gratifying Experience Besides helping clinicians, the information helps put patients at ease. “The exam is not an anxiety-provoking experience,” Dr. Sills explained. “Our technologists and radiologists are superb. They make the experience comfortable, so it’s not a test that patients dread and fear.” The exams are also non-invasive, unlike alternative technologies that are used intra-operatively, and so provide no opportunity for the surgeon to consult with the patient in advance. Dr. Sills notes that the fMRI/DTI data helps inspire confidence in patients and loved ones. He often shows color-coded brain maps to patients before surgery, explaining in simple terms what the images indicate. “I can walk the patients through and show them what we’re looking at,” he added. “Patients and family members can easily understand it. The 693-bed Methodist University Hospital, founded in 1924, is a tertiary care and referral center and the flagship hospital for Methodist Healthcare, a sevenhospital system ranked a Top 100 Integrated Health Network (IHN) by Modern Healthcare magazine. The hospital has a long history of leadership in brain tumor treatment and MR diagnostics. Methodist treated nearly 300 brain tumor cases in 2006, and Le Bonheur Children’s Medical Center, part of Methodist Healthcare, is a major regional referral center for brain tumors. In 1985, Methodist Hospital became the first in its area to offer MR imaging. It has continued to add state-of-the-art MR scanning technology, the most recent purchase being a GE Signa HD 3.0T scanner with fMRI and DTI in November 2006. Other cutting-edge neurological tools offered by this leading facility include magneto encephalography (MEG) scanning and gamma knife surgery. “I think it’s a source of comfort to them to know we have this kind of advanced technology available for planning and studying lesions. It also helps them to understand that we’re doing everything we can to minimize risk.” Hospital staff members at all levels are gratified with the results of fMRI and DTI. Surgeons especially appreciate the technology. “When you’re the guy the patients trust to take them into surgery and bring them out of it safely, you want to have every weapon at your disposal,” Dr. Sills added. “We all learned the classic models of anatomy that tell where functions are located. More and more, we’re finding that those are only approximations, and there’s a lot of variability from patient to patient. There is really no substitute for the real-time, exact, precise information you get from studies like these.” Robert Laster, M.D., a neurointerventionalist with Methodist Healthcare says the technologists are also enthusiastic about fMRI/DTI. “They’re getting feedback from the neurologists and radiologists that, ‘Hey this is helping my patients.’ And the technologists say, ‘This is why I went into the medical field – to help make a difference." Vic Perini, Vice President of Operations at Methodist University Hospital, expects fMRI and DTI technologies to support continued growth in the Neuroscience Institute. “The institute is of vital strategic importance,” he said. “We saw a great opportunity to add differentiating technology that would enable even more outstanding, care for every patient.” A GE Healthcare MR publication • Autumn 2007 47 The information contained in this document is current as of publication of the magazine. BEYOND THE SCAN 1.5T MRI – SIGNA HDE The Right Choice for Your Community: Making the Decision to Add MRI In-house MRI keeps physicians happy and patients closer to home Image courtesy of Hoefer Wysocki Architects Keeping Patients Closer to Home Saunders Medial Center’s new campus. The town of Wahoo, Nebraska is changing. What was once primarily a farming community is now becoming a fast-growing suburb of Lincoln and Omaha, and home to an increasing number of commuters. Until recently, Saunders Medical Center could meet the community’s MRI needs with a mobile service that was onsite for five hours a week. But with Wahoo flourishing and MRI becoming a more widely-used diagnostic test, the demand for exams has grown. “MRI has become a state-of-the-art diagnostic tool for many types of conditions,” said Earl Sheehy, CEO of Saunders Medical Center. “We decided to make the investment in a fixed system in order to improve the quality of care we provide to patients and to make sure they don’t have to wait for an appointment or drive 20-plus miles to get an exam.” 48 A GE Healthcare MR publication • Autumn 2007 According to Patrick Dailey, Manager of Imaging Services, the primary reason was patient and physician satisfaction. “Ordering an MRI exam on Monday and having to wait until Saturday for the procedure is not an ideal situation for the physician or the patient. Having in-house MRI would allow us to provide service seven days a week if we need to.” Competition was another factor. As the demand for MRI services grew, so did the number of scanners in the surrounding communities. At present, there are at least nine fixed MRI systems within 30 miles of Wahoo, from hospital-based systems in Lincoln and Omaha to scanners in freestanding imaging centers. “We knew we were losing a lot of patients to MRI services in the surrounding areas to facilities that offered longer hours and more flexibility in scheduling,” said Dailey. “But why should a patient have to drive 25 miles for a procedure that we could do here, if we had our own scanner?” Encouraging Numbers With plans for the new facility on the drawing board, hospital management floated the idea of acquiring an MRI system to the board, which then authorized a feasibility study. The numbers were encouraging, Sheehy noted. “We determined that about 42 procedures a month would pay for the acquisition and operating costs, as well as the structural expense to accommodate the scanner,” he said. “We were already doing 35 procedures a month with the mobile service and physicians told us that they were referring another 30 to 40 patients a month to other facilities because of our scheduling difficulties. We knew that our volume would go up because physicians would utilize a system that was more convenient for their patients. The information contained in this document is current as of publication of the magazine. 1.5T MRI – SIGNA HDE BEYOND THE SCAN “We showed the board how in-house MRI would improve our ability to provide patients and physicians with better access to quality care. And from a financial perspective, the pro forma revealed that if we averaged just two exams a day, we could easily reach the volume that would justify the decision economically,” said Sheehy. Quality Levels the Playing Field High performance and application flexibility were critical. The hospital wanted to offer a wider range of MRI procedures, such as neurological studies, and provide more advanced applications. The medical center team evaluated a variety of MR systems and manufacturers and selected a Signa® HDe 1.5T MRI system from GE Healthcare. “Image quality was a key factor in choosing the HDe system,” said Dailey. “I’ve also found from past experience working with physicians that they prefer images from a closed MR system versus those from an open scanner.” Virtually all of the imaging equipment that the center uses is from GE Healthcare. “We’ve had a very good history with GE as far as service and technical support are concerned,” added Dailey. “They’re always dependable and willing to help us whenever we need them. That helped make the decision to choose GE very easy.” “MRI needs to be readily available to your patient base. If you make your patients go out of town for these procedures, you’re going to eventually lose them for everything.” Earl Sheehy, Chief Executive Officer Sheehy noted that acquiring a “state-of-the-art” HDe system from GE was also critical from a competitive standpoint. It enabled Saunders to “level the playing field” by offering the same MRI services as those available in larger medical facilities so that patients and their physicians could be assured of receiving superior MRI without having to leave the community. Immediate Physician Buy-in The medical center’s primary medical staff consists of six physicians and two physician assistants who live and practice in the Wahoo area. Referrals also come from approximately 15 specialists who are based in the surrounding communities. The physicians “bought into the idea of in-house MRI the minute we started looking at it,” said Sheehy. The hospital intends to offer the service five days a week in the beginning and add evenings and weekends in the future, based on demand. Athletic injuries and other orthopedic conditions dominate the hospital’s current MRI case mix. Says Dailey, “We have an orthopedic surgeon who holds a weekly clinic at the hospital. There were procedures that he wanted done sooner – and now we’ll be able to have the exams done when he wants them,” said Dailey. “Image quality was a key factor in choosing the HDe system.” Pat Dailey, Manager of Imaging Services A GE Healthcare MR publication • Autumn 2007 49 The information contained in this document is current as of publication of the magazine. BEYOND THE SCAN 1.5T MRI – SIGNA HDE A Technologist’s Perspective “A detachable table can help save a life.” Rachele Malousek, MRI Technologist Rachele Malousek, RT, sees a number of advantages to replacing Saunders’ mobile MRI service with a fixed system. “Patients who have a spine injury or a possible stroke need MRI right away. They can’t wait for a mobile service or to be transferred 30 miles away. Now, we’ll be able to take care of them right away.” She says there will be more time for personalized care, to take better patient histories and visit with patients because technologists won’t have to rush against the clock, trying to get all the cases through in the few hours the mobile system is on-site. Malousek also feels that the hospital will be well poised to stay current with the latest MRI protocols and that turnaround time for reports will be reduced, improving patient care. The information contained in this document is current as of publication of the magazine. 1.5T MRI – SIGNA HDE BEYOND THE SCAN About Saunders Medical Center Malousek is particularly pleased that the hospital selected a Signa HDe system with its unique detachable table. “A detachable table can help save a life,” she said. “If a patient codes or needs help immediately, you just unhook the table and bring the patient outside the magnet room for assistance.” A detachable table also reduces the number of steps in preparing a patient for an exam, she added. “You just move the patient from the bed onto the table, take them to the imaging room and scan them. It eliminates having to transfer patients onto a cart. That saves time and contributes to greater patient comfort.” Malousek has worked with GE systems in the past and feels they are “very user friendly and easy to learn. I’ve trained with GE before and someone is always there to help you, going over the protocols and explaining the software. It’s very reassuring to have someone behind you all the way.” One support tool that Malousek has come to depend on is iLinq™, an exclusive GE service feature that enables users to communicate with GE applications specialists by simply touching a button on the operator console. “If you’re ever stuck trying to figure out something that’s happening with the system, you just push the little button. A GE person always gets back to you within 10 to 15 minutes and usually is able to resolve the issue. It’s very, very cool.” Saunders Medical Center is an independent community hospital in Wahoo, Nebraska, a town of 4,200 in the eastern part of the state. The town sits approximately 23 miles between Lincoln, the state capital, and Omaha, Nebraska’s largest city. The primary focus of Saunders Medical Center is outpatient care. The Critical Access hospital includes full-service laboratory and radiology services, a 24-hour emergency room, physical and respiratory therapy and surgical services. A long-term care facility and a physician clinic are also part of the campus. The facility conducts approximately 6,000 imaging procedures a year. Radiology studies, except for mammograms, are read remotely by a group of board-certified radiologists based in Omaha. Images are transmitted digitally via PACS to the radiologists. Their dictated reports are transcribed at the hospital and distributed to the physicians. The Community is Excited The new GE Signa HDe at Saunders Medical Center became operational in August 2007. “We’re convinced it was the right decision because we’ve heard back from the community how grateful they are that we have a fixed MRI system,” said Sheehy. “Our staff is excited. Our physicians are excited. Our board is excited. Even the county board of supervisors is excited about it.” Sheehy believes that having in-house MRI is essential for an independent community hospital to provide state-of-the-art medicine today – and to continue thriving. “MRI needs to be readily available to your patient base. If you make your patients go out of town for these procedures, you’re going to eventually lose them for everything.” A GE Healthcare MR publication • Autumn 2007 51 The information contained in this document is current as of publication of the magazine. BEYOND THE SCAN REIMBURSEMENT Medicare Reimbursement Update As payors continue to look for ways to rein in the rapid growth in healthcare costs, imaging remains at the forefront of policy and cost debates. Understanding, following and acting upon the numerous complexities of proposed reimbursement changes is challenging for many healthcare providers to manage. To support customers in understanding this continuously evolving and highly regulated area, and to ensure that all customers have access to the latest information and resources, GE Healthcare has a dedicated website on reimbursement that includes: • The latest Medicare Payment Rates for procedures in all the major imaging modalities including listings by site of care and geographic area • Links to Payer Medical Policies to help providers understand the conditions under which a given procedure may be covered • GE Reimbursement Customer Advisories with coding, coverage and payment information For MRI, recently updated Customer Advisories include Breast MR Imaging, Breast MR Biopsy and Functional MRI (fMRI). These documents are posted on GE’s reimbursement website (www.gehealthcare.com/reimbursement). Education and awareness is only one aspect of what GE Healthcare is doing to support medical imaging customers. Under the guidance of Mike Becker, General Manager of Global Reimbursement and John Schaeffler, General Manager of GE Healthcare Government Relations, GE has been working to identify current and future customer imaging risks and developing various strategies to mitigate these risks. To this end, GE continues to partner with strong industry organizations to protect and preserve access to quality imaging for all patients and to stabilize the market after the shock of the DRA (Deficit Reduction Act). GE is a founding member of the national Access to Medical Imaging Coalition (AMIC) comprised of equipment manufactures, healthcare providers, key medical societies and patient advocacy groups that represent more than 75,000 patients, physicians, and imaging providers. GE serves on the executive board of AMIC and like other participating members, contributes resources to support the public relations, 52 A GE Healthcare MR publication • Autumn 2007 advocacy and educational activities aimed at ensuring access to imaging. More information can be obtained at the AMIC website (www.imagingaccess.org). GE also joined AdvaMed in 2007, a successful, international medical device industry association representing over 1300 companies and subsidiaries. GE plays leadership roles in this organization with Joe Hogan on the Board of Directors and Mark Vachon as the Vice Chair of the newly created Diagnostic Imaging sector. There is also broad GE Healthcare participation at the working group level to engage on important customer topics such as payment advocacy, state legislation, and quality. As a long-term member, GE continues to strongly influence the advocacy program for the Medical Imaging & Technology Alliance (MITA), a division of NEMA (National Electrical Manufacturers Association), which represents companies whose sales comprise more than 90 percent of the global market for medical imaging technology. Jim Davis, Vice President and General Manager of the GE Healthcare MR Business chairs the MITA section. MITA has focused on educating lawmakers, the media and key stakeholders on the “Value of Imaging” (www.medicalimaging.org) with a formal public relations campaign. For more information, please visit www.gehealthcare.com/ reimbursement. The information contained in this document is current as of publication of the magazine. E D U C AT I O N – P E E R V I S I O N : S I G N A 3 . 0 T S O C I E T Y B E Y O N D T H E S C A N Figure 1 The GE Signa 3.0T Society welcome page on the PeerVision Online Community web site. Signa 3.0T Users Share Best Practices, Clinical Techniques with Users Around the World Launched September 2007, the GE Signa 3.0T Society on the PeerVision Online Community web site brings Signa® MR 3.0T Users together to interact and learn from one another. Through PeerVision, users can openly share ideas or opinions, forming an online community with user-generated content that shares the latest techniques in 3.0T imaging across the globe. Within the Signa MR Imaging Community, users will find MR educational opportunities and events. The GE Signa 3.0T Society includes discussion forums, polls, a gallery for clinical case images and a library of tools and tips. Guest bloggers periodically post topics for open discussion and participants can elect to share comments on the topic or merely read along with the dialog. PeerVision is the result of research on MR-users’ information needs, incorporating customer feedback to create a “nonpromotional” environment for authentic communication among Signa MR 3.0T Users. PeerVision has several online communities for users with different interests to join and participate in any discussion, including: Advanced Visualization, Outpatient Imaging Centers and Reading Rooms. The GE Signa 3.0T Society is open only to Signa MR 3.0T Users. The System ID, found on or near the Signa MR 3.0T System Monitor, is required for initial log in. Join the community today, www.healthcare.com/peervision. With PeerVision, you can • Join a discussion on imaging challenges or share a clinical case • Find out what your peers think, or share your own insights PeerVision. It’s your community – GE provides the medium. You decide how it evolves. A GE Healthcare MR publication • Autumn 2007 53 GE Healthcare A breast MR solution designed for breast MR — without limitations. Imagine that. In breast MR, diagnostic confidence comes with being able to identify critical lesions. And that kind of clarity comes with the Signa® breast portfolio, the only portfolio designed specifically to be a breast MR solution. And the most comprehensive HD solution available for breast MR. It starts with VIBRANT, the first ever bilateral, volumetric acquisition technique introduced for breast, and still the industry standard for speed and resolution. And it’s supported by BREASE, a breast-specific proton spectroscopy solution, CADstream™ automated analysis and reporting to drive efficient workflow, and the HD Breast Array that enables outstanding image quality and easy access for procedures. Combine all this with the Vanguard Breast Table™ from Sentinelle Medical, and these solutions add up to excellent specialization capabilities and diagnostic confidence. When Breast MR is technology’s focus, every detail becomes very clear. Breast MR Re-imagined. Visit GE Healthcare at RSNA Booth #1929 imagination at work © 2007 General Electric Company.