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imagination at work

Spectral CT: A Brave New World of Quantitative, Functional Imaging1

CTA Changing Patient Management in the EDPage 26

T H E M A G A z I N E o F C T • J u N E 2 0 1 1

§ Veo is 510(k) pending at FDA. Not commercially available in the united States.

§Veo Ultra Low Dose – p. 32

Veo: A New Breakthrough is Re-writing the Rules of Low-dose CT ImagingPage 32

2 A GE Healthcare CT publication • June 2011

C o N T E N T ST A B L E o F

Publications Team:

Kelley Knutson & Jodi Young CT Clarity Editors CT Education Managers

John Allenstein Marketing Communications Manager CT and Advantage Workstation

Mary Beth Massat Writer/Editorial Consultant

Nilesh Shah Chief Marketing officer, CT

J. Eric Stahre General Manager, Global Premium CT

Integré Design/Production

Jennifer Coppersmith Design/Production Consultant

GE Contributors:

Andrew Ackerman CT Marketing Manager

Olivier Adda CT Super Premium Strategic Product Manager, Europe, Middle East & Africa

Dr. Karthik Anantharaman CT Marketing Manager, South Asia

Christophe Argaud CT Advanced Applications Manager, Europe, Middle East & Africa

Paul Ayestaran Advanced Applications Specialist, Europe, Middle East & Africa

Chelsea Beeler Communications Manager

Chuck Bisordi CT Product Development Specialist

Valerie Brissart CT Marketing Director, Europe, Middle East & Africa

Morris Buliva Account Manager, East Africa

Roger Cepeda Associate General Counsel, Diagnostic Imaging

Lawrence Chia CT Modality Manager, Southeast Asia, Australia & New zealand

DeAnn Haas CT Marketing Manager, Leadership Segment, Americas

Takuya Hiramoto Product Marketing Specialist, Japan

John Jaeckle Regulatory Affairs Manager

Gina Larkin CT Marketing Manager

Huayang Liu China HDCT Product Leader

Pascal Lucien CT Modality Manager, Africa

GE Healthcare News

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

South America Embraces the Latest GE CT Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

New Tools to Analyze Vessel Lumen, Diseased Tissue . . . . . . .6

Quantitative Assessment of the Lung . . . . . . . . . . . . . . . . . . . . . . .6

unravelling the Mystery Behind Mummies . . . . . . . . . . . . . . . . . .7

GSI Shines at Conferences, Journal Competition . . . . . . . . . . . .8

optima CT660‡ Reaches Milestones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

First-time CT users Embrace Brivo CT325 . . . . . . . . . . . . . . . . . 10

Clinical Value

Spectral CT: A Brave New World of Quantitative, Functional Imaging . . . . . . . . . . . . . . . . . . 11 - 19

Making Reliable Low-dose CT a Clinical Reality . . . . . . . . 20 - 24

CTA Changing Patient Management in the ED . . . . . . . . . . . . . . . . . . . . . . . 26 - 29

Kenya Hospital Extends Quality CT Imaging to More Residents . . . . . . . . . . . . . . . . 30 - 31

Veo‡: A New Breakthrough is Re-writing the Rules of Low-dose CT Imaging . . . . . . . . . . . . . . . . . . . 32 - 37

Reaching New Heights in CT Cardiac Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 - 39

Eco, Patient, and Physician Friendly: Advanced Low-dose Imaging Without Compromise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 - 41

Make Every Study Exceptional . . . . . . . . . . . . . . . . . . . . . . . 42 - 43

GE Healthcare News: First-time CT users Embrace Brivo CT325§

page 10

Clinical Value: Making Reliable Low-dose CT a Clinical Reality page 20

Case Study: CT Perfusion 4D Imaging in Stroke Assessmentpage 48

3A GE Healthcare CT publication • June 2011

C o N T E N T ST A B L E o F

Beyond the Scan: Working Together Towards the Sub-mSv CT Exampage 69

© 2011 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.

Beyond the Scan

Techniques to Lower CT Dose . . . . . . . . . . . . . . . . . . . . . . . . 66 - 68

Working Together Towards the Sub-mSv CT Exam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 - 71

CT Clinical Education in the uS, Europe, Middle East, and Africa . . . . . . . . . . . . . . . . . . . . . . 72 - 73

Technical Innovation

System Design Combines High Performance with Patient, Earth Friendliness . . . . . . . . . . . . . . . . . . . . . . 53 - 55

one Seamless Workflow Environment . . . . . . . . . . . . . . . . 56 - 58

The Importance of Spatial Resolution for High-quality Cardiac CT Exams . . . . . . . . . . . . . . . . . . . 59 - 62

The Model-based Paradigm: A New Frontier in Image Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 - 65

Case Study

High Quality, Reduced Dose Imaging in the Comprehensive Evaluation of Potential Kidney Donors . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 - 45

Characterization of Renal Stones using GSI . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 - 47

CT Perfusion 4D in Stroke Assessment . . . . . . . . . . . . . . . . 48 - 49

Low-dose CT Imaging of CPAM for Surgical Planning . . . . . . . . . . . . . . . . . . . . . . . . 50 - 52

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Technical Innovation: The Model-Based Paradigm: A New Frontier in Image Reconstructionpage 63

Andrew Menden Regulatory Affairs Leader

Thierry Modica CT-AW Advanced Application Specialist, Africa

Daniel Morris CT Global Marketing Manager

Enrique Garcia-Muñiz CT Marketing Manager, Latin America

Christoph Obermeier CT Clinical Education Business Manager, Europe, Middle East & Africa

Tracey Ortiz Regulatory Affairs Leader

Konstantin Osadchiy, MD, PhD CT Advanced Applications Specialist, Russia & CIS

Helen Peng Regulatory Affairs Leader

Karen Procknow CT Product Development Specialist

Linda Pucek CT Segment Marketing Manager, oncology, Americas

Dario Salvadori CT Performance & Value Strategic Product Manager, Europe, Middle East & Africa

Saad Sirohey, PhD Global Product Manager, CT Advanced Applications

Stephen Slavens Regulatory Affairs Director, AW

Cristian Toader CT Premium Strategic Product Manager, Europe, Middle East & Africa

Wayne Zhang Marketing Product Manager

* Discovery, optima, Brivo, ASiR, Veo, LightSpeed, BrightSpeed, Gemstone, SnapShot, SmartmA, AutomA, Performix, VCAR, Volara, VolumeShuttle, Dexus, Centricity, CardIQ, and AppsLinq are trademarks of General Electric Company.

§ Brivo CT325 is not for sale in the united States. Not cleared by the uS FDA.

‡ optima CT660 and Veo are 510(k) pending at FDA. Not commercially available in the united States.


WelcomeSteve Gray, Vice President and General Manager, Computed Tomography, GE Healthcare

§ Veo is 510(k) pending at FDA. Not commercially available for sale in the united States.‡Brivo CT325 is not for sale in the united States. Not cleared by the uS FDA.

At GE Healthcare CT, we believe that great care happens by design. our organization makes decisions regarding CT product development with one purpose in mind: to help healthcare providers deliver the best patient care. You, our customers, have spoken and we heard your voices loud and clear.

You told us you want to deliver high image quality for diagnosis at ever lower doses for all of your patients who need a CT. We heard that you want to expand the diagnostic capabilities of CT—to let you know more about the pathology you are viewing to aid you in making precise, confident clinical decisions. You want a CT system with high spatial resolution to deliver excellent image quality that drives advanced applications and productivity.

In this issue of CT Clarity, you can read how GE Healthcare is delivering solutions to address your clinical needs and to help you provide great care to your patients.

on page 11, read how Gemstone* Spectral Imaging (GSI) is opening up an exciting and promising new world for CT imaging—where clinicians can obtain quantitative information on tissue characterization, reduce artifacts from metal instrumentation, and enhance contrast material.

In an article on spatial resolution (page 40), you can learn how the high spatial resolution on the Discovery* CT750 HD improves cardiac CT imaging and why it is an important consideration as you investigate solutions that improve cardiac care at a lower dose.

We introduced three new systems that are designed with great care to expand the reach of CT to patients throughout the world. These include the optima* CT660§ system that is ecomagination and healthymagination validated (page 42); the BrightSpeed* Elite that demonstrates our commitment to bring advanced applications and dose lowering technology across our product platforms (page 44); and the Brivo* CT325,‡ a system that extends modern CT technology to healthcare facilities so they can provide advanced medical imaging services to their patients—patients who may otherwise not have access to CT imaging (page 32).

For over three decades, GE has made a commitment to developing technologies that lower radiation dose. our long-standing vision is clear—to be a leader in patient-centric solutions, to design systems that deliver high-performance imaging, and to continue developing innovations that drive even lower dose.

But how low can we go? At GE Healthcare, our goal is the 1 mSv study across all pathologies, anatomies, and studies. Lowering dose is a core commitment in our effort to deliver great care by design. In past issues of CT Clarity, you’ve read how dose-reduction technologies like ASiR* deliver high image quality while lowering dose. Now, in this issue, we present our latest dose-lowering advancement, Veo§.

Veo is our next generation dose-lowering technology. Learn how several healthcare providers around the world have achieved remarkable breakthroughs in high-quality, impressively low-dose CT imaging with Veo (page 34). We believe this new technology will play a key role in moving us toward our goal of the 1 mSv study across all exams and will help you achieve your diagnostic needs at before unheard of doses without any compromise in image quality. In fact, you’ll learn that some clinicians actually experienced an increase in image clarity while they reduce dose when using Veo. Clearly, the rules of CT imaging have changed.

Read on and you’ll understand why we at GE Healthcare are so excited about the future of CT. This last decade was a phenomenal one—widespread adoption of the multi-detector CT was heralded as a major advancement in medical imaging. At GE we’ll continue to pursue innovation that drives a more confident diagnosis at the lowest dose in the delivery of care—together with you, great care by design can impact healthcare across the world.

Please read and enjoy. And as always, thanks for your continued support.


G E H E A LT H C A R E N E W SA N N o u N C E M E N T S

Advances in CT generate excitement in Southern Brazil

Powered by the first new CT scintillator material in two decades, the Discovery* CT750 HD generates excellent, high definition image quality. This capability inspired Carlos Jader Feldman, MD, at SIDI – Medicina por Imagem (Porto Alegre, Brazil) to select the Discovery CT750 HD and become the second site in South America to acquire this system.

Anticipating tomorrow’s needs, Dr. Feldman saw the ability to capture high definition images that characterize complex lesions, such as coronary artery stenosis, as the most impressive benefit to his patients and practice. “I believe the Discovery CT750 HD will allow me to accurately diagnose ischemic patients,” he says. With excellent image clarity and spatial resolution, Dr. Feldman expects the system will allow for faster clinical decisions by clinicians.

Located in Brazil’s fourth largest metropolitan area with nearly four million inhabitants, SIDI and Dr. Feldman have long trusted GE Healthcare’s technological leadership. While it was a natural choice to look to GE for the next generation in CT imaging, Dr. Feldman saw the potential of Gemstone* Spectral Imaging (GSI) to help him deliver a new level of care to his patients.

“Today’s clinical path leads to anticipating etiology of diseases, thus, it means earlier diagnostics and more accurate treatments,” he says. With GSI, HD, and ASiR* * all available on one system, Dr. Feldman is thrilled at the potential to deliver a higher level of exam accuracy while enhancing patient comfort. “I will be able to provide patients and referring physicians a confident CT diagnosis and broader range of exams,” he adds.

Low-dose CT makes its mark in Argentina

Innovative leadership. That’s how Dr. Sergio Julio Moguillansky, Director of Medicina XXI SA (Neuquen, Argentina) describes GE Healthcare and its exclusive ASiR dose lowering technology.

“The concept of reducing dose whenever possible to achieve the appropriate diagnosis is inherent to our specialty,” he says.

“Thus, we consider every technological advance that allows us to reduce the dose a priority.”

The hospital recently installed ASiR technology on its LightSpeed* VCT and is experiencing dramatic low-dose results. While the actual dose level is closely related to the type of exam and the expected results required for appropriate patient management, Dr. Moguillansky is excited to offer less dose to his patients who are becoming increasingly aware of CT radiation dose.

“Patients are addressing the dose issue with our clinicians, most notably the pediatricians,” he says. “With ASiR, we can demonstrate our commitment to providing the proper diagnosis through the ALARA principle.”

At Medicina XXI SA, CT imaging volume averages 40 patients each day across a wide spectrum of indications—abdominal, thoracic, vascular, and neurological conditions. High-quality and fast imaging capabilities are a primary objective at the facility, says Dr. Moguillansky. By offering substantial dose reductions at a similar image quality, ASiR fulfills the facility requirements and helps alleviate concerns over dose.

“our expectations are very high,” adds Dr. Moguillansky, “and we are pleased to implement this technology due to the increasing benefit that it will bring to our clinical practices and particularly, to our patients.” n

South America Embraces the Latest GE CT Technologies

“I will be able to provide patients and referring physicians a confident CT diagnosis and broader range of exams.”

– Dr. Carlos Feldman** In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task.


G E H E A LT H C A R E N E W S A N N o u N C E M E N T S

CT imaging is changing the way clinicians diagnose cardiac disease. Yet, the large volume of data generated by today’s advanced systems can impede workflow if clinicians don’t have the right tools to process the information. As an integral part of Dexus*, CardIQ* Xpress Reveal, streamlines your workflow so that exams of the heart and coronary anatomy are ready to review the instant you’re ready to read.

Two enhanced tools are designed to help clinicians improve their diagnosis. The new PlaqID plaque analysis tool allows clinicians to visualize both calcified and non-calcified plaque to determine the amount of atherosclerosis. This new tool also offers

customizable color mapping to improve visualization of plaque pathology for a better understanding of the severity of disease.

The GE exclusive relative perfusion tools use sophisticated segmentation techniques to color code the myocardial tissue. Hypodense lesions are displayed to better visualize ischemic heart disease to aid in treatment planning. Plus, the new hybrid display view combines the coronary arteries and perfusion map to correlate the vessels to diseased tissue.

CT is an excellent non-invasive alternative for diagnosing coronary artery disease. using CardIQ Xpress Reveal speeds assessment of the patient’s cardiac disease state by delivering more information in a simpler, faster, smarter way. n

New Tools to Analyze Vessel Lumen, Diseased Tissue

Coronary tree Cardiac perfusion PlaqID

Now available, Thoracic VCAR* provides the physician with a set of quantitative tools that will aid the physician in the assessment of thoracic disease diagnosis and management. The software provides automatic segmentation of the lungs and airway tree, as well as tracking of the airway tree. The software will also provide the quantification of Hounsfield units and display by color the thresholds within a segmented region.

Key features include:

• Automated segmentation of right and left lung airways— ease of use assists in quantification of lungs and airways;

• one touch 3D airway tracking with automated measurements—simple user interface aids in analysis and review;

• Lung Lobe segmentation—intuitive interactive lobe segmentation that allow for reporting of quantitative measurements by lobes; and

• Parenchyma analysis—parenchyma protocol for generating quantitative measurements displayed as percentage/liters of volumes of abnormal density.

Together these capabilities provide an integrated application for a comprehensive evaluation of a lung CT image. The analysis tools are married to an easy-to-use reporting capability that

automatically captures the analysis results. The end result is a clear and concise clinical report that is generated during the reading process and specifically designed for the communication of vital medical information to referring clinicians and patients. n

Quantitative Assessment of the Lung

Parenchyma analysis

Volume rendering segmented lobes with segmented trachea

Lung lobe segmentation



Finding out the details underneath the bandages of the mummies from the Milwaukee Public Museum is what Carter Lupton, PhD, Curator of Ancient History, Department Head at the museum, hopes to do thanks to the most advanced CT technology by GE Healthcare, the Discovery* CT750 HD. Three of the mummies from the museum collection were scanned in April, 2011 to find out more information about their gender, age and causes of their death.

In collaboration with GE Healthcare, researchers from the Milwaukee Public Museum used the latest GE CT imaging technology to look back through time and start unraveling details about how three mummies—two from ancient Egypt and one from Peru—lived and died.

This isn’t the first time the anthropologists have turned to GE Healthcare for assistance, and as GE’s CT imaging technology has improved, so too has their knowledge of the mummies’ history. one of the Egyptian mummies, named Djed-Hor, was first scanned in 1986.

Then again in 2006, another scan using better technology revealed a silver dollar-sized hole in his skull, leading the anthropologists to conclude he had undergone a primitive form of brain surgery.

To best help the museum unravel the mummy mystery, GE Healthcare provided a cutting-edge Discovery CT750 HD along with Gemstone* Spectral Imaging (GSI), which offered high quality images and a dramatic level of detail. GSI also allows researchers to distinguish

one type of tissue from another in order to better understand the makeup of the mummies’ bodies

and other material.

Dr. Lupton and his research team used the high resolution images from the CT scanner to learn more about ancient medical skills and knowledge,

as well as create 3D holographic representations of what the mummies would have looked like when they were alive.

“We’ve been doing this for 25 years with GE. Every time we’ve come out, it’s a different generation of technology, better imaging, better information, better ways, and it’s faster too,” Dr. Lupton added. n

unravelling the Mystery Behind Mummies

An ancient Egyptian mummy is scanned.

CT scan of a Peruvian mummy.



GSI Shines at Conferences, Journal CompetitionAmerican Society of Spine Radiology

At the American Society of Spine Radiology (ASSR) conference, Dual Energy Spectral CT of the Instrumented Spine: Tuned Monochromatic Imaging Improves Quality over Traditional Techniques won third place in the Mentor Award Program. The authors, James M. Kessler, MD, MPH; J. Rios, MD, PhD; M. Ellestad; P. Pawha, MD; A. Doshi, MD; E.G. Stein, MD, PhD; and Lawrence N. Tanenbaum, MD, FACR, demonstrated how employing Gemstone* Spectral Imaging (GSI) in patients post-spinal fusion produced excellent image quality with reduced spinal canal artifact and optimal hardware visualization.

“Historically, quality imaging of the spine in patients post hardware fusion remained fraught with prohibitive artifacts utilizing traditional polychromatic CT scanners,” explains Dr. Kessler.

The authors displayed examples of CT myelography with and without the benefits of spectral imaging and demonstrated a markedly improved capacity for clear visualization of the central spinal canal and its contents, including the spinal cord and nerve roots. Dr. Kessler notes that in many cases, spectral CT myelography differentiated soft tissue in a similar manner to MRI allowing for optimal depiction of the nerve roots and adjacent soft tissue structures.

“This technique virtually eliminates the artifact,” he explains, “and the ability to generate the same high quality exam as we would expect in non-instrumented patients opens up a new opportunity for patient management in those who might otherwise have persistent chronic symptoms.”

Society of Gastrointestinal Radiology

GSI won two different awards at this year’s Abdominal Radiology Course meeting, a joint meeting of the Society of Gastrointestinal Radiology (SGR) and the Society of uroradiology (SuR). The first place paper from the SuR was awarded to Jessica Ruhland, MD; Amy Hara, MD; Alvin Silva, MD; Rishi Gosalia, MD; and Qing Wu, MD, of the Mayo Clinic Arizona for the Assessment of Renal Lesion Enhancement: Comparison of Single and Dual Energy CT.

According to Dr. Ruhland, the study reported on the evaluation of five image datasets by two radiologists blinded to diagnosis: 140 kVp; 70 keV monochromatic; material density (MD) water/iodine; MD iodine with color; and attenuation curves from 40 to 140 keV.

“We found that the readers had improved sensitivity, specificity, and diagnostic confidence when using the material density images with color and the attenuation curves compared to 140 kVp or 70 keV images alone,” Dr. Ruhland says. “of clinical importance is that using the spectral CT data, the radiologists were able to accurately determine whether the renal lesion was enhancing or non-enhancing, thereby avoiding unnecessary and costly additional tests.”

Dr. Ruhland acknowledges that while further study is needed, she is hopeful that this first place paper demonstrating the successful use of spectral CT to characterize renal lesions will ultimately help reduce healthcare costs associated with working up indeterminate renal lesions seen with CT.

Also at SGR, the university of Alabama at Birmingham earned the award for First Place Poster. Desiree E. Morgan, MD, Vice Chair for Clinical Research, accepted the award for the poster, Dual Energy Spectral MDCT of the Pancreas: Imaging Beyond Anatomy.

“The poster captures an exciting new area that deserves further exploration by demonstrating the large number of applications for spectral CT imaging,” says David N. Bolus, MD, Assistant Professor, a co-author.

Dr. Morgan agrees that spectral CT created excitement and “a groundswell such that I have not seen before at a clinical symposium. The images were clearly different than traditional CT—my fellow gastrointestinal radiologists and genitourinary radiologists all wanted to learn more about this intriguing new technique.”

“The ability to capture material density,” Dr. Morgan continues, “and quantitatively differentiate things such as fat and iron in the liver, for example, is quite remarkable.”

Drs. Morgan and Bolus stress that what is truly important will be the future impact on patient care—and how radiologists, by utilizing spectral CT, can aid referring physicians in making patient management decisions. Adds Dr. Bolus, “When our research helps propel further utilization of a technique, so that it is widely used throughout the medical community, then for us it truly becomes ‘groundbreaking’.”



Chinese Journal of Radiology

Initiated by renowned radiology opinion leaders and senior editors, the Chinese Journal of Radiology (CJR) held the Spectral CT Research Paper Competition in September, 2010.

Thirty-four spectral CT research papers were submitted covering in-vitro experiments, impact on image quality, artifact reduction, tissue characterization, differentiated diagnosis in oncology, hemodynamic studies, and therapy evaluation.

After the thorough evaluation, the committee selected eleven papers—all using GE Healthcare’s GSI—for publication in the Spectral CT Special Edition this past spring.

Professor Hong Gao, Editor-in-Chief of CJR, says, “CT Spectral Imaging is an exciting new study area of radiology. From all of the 34 submitted research papers, we saw its fundamental impact on our CT practice and research. We look forward to more promising clinical applications and research in the future.” n

GE Healthcare is pleased to announce the 100th optima* CT660§ will be delivered to olbia Hospital in Sardinia for the S. Raffaele Foundation. Since the global introduction of the system in April, 2010 over 200 orders worldwide have been received.

of the 200-plus orders, nearly half of the sites are installed and operational as of April, 2011. This high demand demonstrates that the optima CT660 is answering the clinical imaging needs of radiologists.

Program, and Dr. Mohammad Alshaji, Director of the Medical Department, and the Royal Commission Hospital team to celebrate the installation of this new system. This new system will deliver excellent CT imaging to the Al Jubail area in the Eastern Province of the Kingdom of Saudi Arabia.

Inauguration symposium at St. Rembert Hospital

An inauguration symposium took place in Torhout, Belgium at the St. Rembert Hospital—the first European site to receive the optima CT660 with ASiR and overlapped Reconstruction options. The overlapped Reconstruction feature enables 128 slices per axial rotation.

The symposium included invited speakers on cardiac CT and dose reduction technologies, a live demonstration on post-processing applications, and a lecture comparing CT with conventional radiology.

St. Rembert is a medium-sized hospital with a 250-bed capacity and offers healthcare services to a population of 50,000 in West Flanders. The CT system is being used for all protocols, including emergency, cardiovascular, and cardiac imaging, and current daily patient volume is approximately 40 patients.

Geert Bibau, MD, Chief of the Radiology Department, explained that among the reasons for choosing optima CT660 with ASiR were the excellent post-processing capabilities and dose reduction technologies. n

optima CT660 Reaches Milestones

§optima CT660 is 510(k) pending at FDA. Not commercially available in the united States.

Royal Commission Hospital Team

Royal Commission Hospital

GE Healthcare recently installed the first optima CT660 with ASiR in the Middle East region. The local GE team joined Mr. Abdul-Rahman Alhewar, Director of Health Service

10


A head exam on Brivo CT325 at Anhua Traditional Chinese Medicine Hospital.

Across the world, healthcare providers who are first-time CT system buyers are discovering they don’t have to compromise between value and performance. The Brivo* CT325§, a GE Healthcare CT scanner developed and manufactured in China, achieves the balance of an attainable, reliable, and capable CT scanner.

“This is reverse innovation at its best,” says Wayne zhang, Product Manager, GE Healthcare, China. “We’ve designed the Brivo CT325 with advanced GE technologies and leading-edge features in an ultra-compact, space-saving system that provides the efficiency and resolution required for many types of routine CT procedures.”

Brivo CT325 was created with the new user in mind—by reducing the number of steps needed to position and release the patient, the table design helps streamline CT exam workflow and increase throughput. The operating console combines both image acquisition and post-processing with advanced applications, simplifying management of multiple tasks from a single location.

“The Brivo CT325 imaging capabilities fulfill the various clinical needs of the average user,” says Qui Jianxing, MD, PhD, Peking university First Hospital and the clinical evaluation site for the system. “The system is very reliable, enabling us to scan patients all day.”

Reliable, high-quality imaging is assured with Auto mA to improve signal-to-noise ratio and optimize dose; the bowtie X-ray beam-shaping filters to maintain uniform X-ray at the detector, minimize surface dose, and reduce X-ray scatter; the beam-tracking system, which contributes to higher dose efficiency by automatically measuring the position of the beam and adjusting the collimator using data transferred in real time; and, the high-absorption efficiency (98%) and stability of GE detectors for high image quality with optimized dose.

Just as the compact system fits new users’ needs, GE’s service and support is designed to offer the same. The latest advances in service technology, such as remote diagnostics, help maximize system uptime and resolve many service calls remotely. Maintenance and service elements coupled with comprehensive, flexible training solutions, enables each organization to meet its service and support needs.

“The images and the applications are excellent and reliable,” says zeng Xianming, MD, Director of the Radiology Department, Anhua Traditional Chinese Medicine Hospital, Hunan province.

“With the speed of the system, we can image as many as 30 to 40 patients in one day without any overtime scanning. This has helped us provide better support to other departments in the hospital.”

Brivo CT325 combines simplicity with performance— incorporating CT perfusion, CT colonography, vessel analysis, and advanced volume analysis including averaging, MIP, MinIP, and volume rendering.

“Priced affordably for facilities that couldn’t previously afford to implement CT, Brivo CT325 embraces GE’s healthymagination initiative and increases access to CT imaging,” zhang adds.

In fact, for 67% of the sites implementing Brivo CT325, this is the first CT system purchased. After a successful launch in China, Brivo CT325 was introduced in Asia-Pacific, India, Latin America and Africa. Learn more how one facility in Kenya— Jocham Hospital—is using the Brivo CT325 to better serve its patients (page 32). n

First-time CT users Embrace Brivo CT325

Qingdao No. 5 People’s Hospital.


A GE Healthcare CT publication • June 2011


C L I N I C A L V A L u EG E M S T o N E S P E C T R A L I M A G I N G

CT has long been considered an excellent method for viewing high-resolution images of human anatomy in a non-invasive manner. It has been used in conjunction with PET and MRI—devices that can image tissue and organ function—to bring together anatomic and morphologic information for a more precise patient diagnosis and treatment plan.

While CT is “an excellent technique with good spatial and temporal resolution, the soft tissue contrast and ability to discriminate normal and pathological tissues is sometimes inferior to other imaging techniques,” says Valentin Sinitsyn, MD, PhD, Chief of the Radiology Department at the Federal Center of Medicine and Rehabilitation (Moscow) and Professor and Chair of Radiology, School of Fundamental Medicine at Moscow State university. This limitation has led to the utilization of other functional imaging techniques in conjunction with CT imaging—which may result in additional studies and potentially higher healthcare costs.

However, CT is closing the gap between anatomical and alternative functional imaging thanks to advances in spectral CT and the introduction of Gemstone* Spectral Imaging (GSI) on the Discovery* CT750 HD scanner. Today, GSI is beginning to change the way radiologists across the world utilize CT imaging.

“GSI’s spectral Hu curve and material-basis analysis provides us with information on material characterization and quantification—this is revolutionary.”

– Prof. Xiao-Peng Zhang

Spectral CT: A Brave New World of Quantitative, Functional Imaging


C L I N I C A L V A L u E G E M S T o N E S P E C T R A L I M A G I N G

“GSI is breaking down a barrier by bringing a new type of functional imaging to CT,” explains Jean-Nicolas Dacher, MD, PhD, Professor of Radiology and Diagnostic Imaging and the Chief of the Department of Diagnostic Imaging at Rouen university Hospital, (France). He routinely uses GSI, performing approximately 20 cases each week. “Plus, with CT we have the advantage of a quick examination that can be more comfortable for the patient,” he adds. This is compared to traditional functional imaging studies (MR, SPECT and PET) that can last a minimum of 20 minutes to one hour, an important consideration for very sick and elderly patients.

After conducting more than 1,500 GSI scans and 20 pilot studies in the first three months of using GSI, Xiao-Peng zhang, MD, Professor and Chairman of Radiology, Peking university Cancer Hospital and Institute (China), clearly sees its clinical value.

“We believe GSI will change the way that doctors practice and interpret CT,” he says. “GSI’s spectral Hu curve and material-basis analysis provide us with information on material characterization and quantification—this is revolutionary.”

Revolutionary is a statement echoed by Lawrence Tanenbaum, MD, FACR, Director of MRI, CT, and outpatient/Advanced Development, Mt. Sinai School of Medicine (uSA).

“Spectral CT offers potentially revolutionary information when compared to traditional polychromatic CT,” he says, “including the ability to reduce certain artifacts, such as streak and beam hardening from metal, enhance contrast resolution that will perhaps make iodine more or less conspicuous, or improve contrast resolution by alternating energy levels to differentiate two different tissues.”

Tissue characterization

GSI enhances tissue characterization through its ability to derive images that separate materials such as calcium, iodine, and water.

“What really impresses me is the rich tissue characterization capability of spectral CT,” says Dr. Tanenbaum. “To look at a dense brain lesion and know whether it is hemorrhagic, enhancing or calcified is very helpful, particularly in difficult case scenarios.”

The 101 selectable energies and monochromatic images of GSI, explains Prof. zhang, enable easier and clearer detection of extremely tiny structures—for example, the pancreatic duct and membranous structures such as the greater omentum. “This is rarely achieved using conventional CT,” he adds.

Gemstone Spectral Imaging

Gemstone Spectral Imaging (GSI) is a dual-energy scan mode that acquires data of an object by rapidly switching between low kVp and high kVp energies in less than half a millisecond. This generates data with different attenuation values based on the corresponding energy levels. The result is a near-perfect, simultaneous dual-energy acquisition at the full 50 cm scan field of view (SFoV) producing projection (raw) data at two different energy levels that has virtu-ally no misregistration. This enables raw data-based reconstruction of dual-energy data with the associated benefits of quantitative material decomposition and beam-hardening reduction from monochromatic energy synthesis.

Projection-based reconstruction is used to process the data. Based on known attenuation curves, the process mathematically transforms low and high kVp attenuation measurements into effective material density (MD) basis-pair images. This is also known as material decomposition. GSI produces these MD pairs which are not available with conventional contrast-enhanced CT imaging. The make-up or composition of the MD pairs can be selected based on the clinical question being investigated and materials of interest, such as iodine-water, iodine-calcium, or water-calcium. GSI also produces a monochromatic image, which is synthesized from the MD images and depicts how the object would look if the X-ray source produced only X-ray photons at a single energy.

Specific tools have been created in the GSI Viewer to support the data analysis of this rich information. Tissue characterization can be aided with the help of Hounsfield unit (Hu) spectral curves; metal artifact reduction is enabled by interactively switching to the optimal monochromatic energy level. Additionally, material identification is made possible by displaying the effective atomic number histograms of objects, particularly kidney stones.

“With the GSI-generated iodine maps, I can clearly see the severity of perfusion deficit.”

– Prof. Valentin Sinitsyn



Pulmonary embolism

GSI represents what is lacking in a typical CT study, says Prof. Sinitsyn. After the Discovery CT750 HD scanner with GSI was installed at the Federal Center in November 2009, he immediately began investigations on pulmonary emboli.

“Traditionally, CT provided an excellent depiction of the pulmonary vessels, thrombi and emboli,” he explains. “However, it could not give us full information on the severity of pulmonary embolism obstruction or perfusion deficit defects. With the GSI-generated iodine maps, I can clearly see the severity of perfusion deficit.”

upon closer review, Prof. Sinitsyn discovered he could also detect tiny thrombus or embolus inside the pulmonary artery, which often causes the perfusion defect.

“In patients with chronic embolism,” he adds, “it is clear that if we see multiple perfusion defects there exists a strong indication to support surgical removal of the thrombi.” He cites a recent study where the occurrence and severity of the perfusion defect as determined by spectral CT is a strong predictor of patient prognosis.

Prof. Dacher also uses GSI on a daily basis to generate iodine maps for lung perfusion studies (by centering the images on the iodine). Most exciting, he says, is the capability to view the pulmonary artery anatomy for helping to detect clots at the same time he obtains a lung perfusion map. He can then use the anatomical and functional information—obtained during the same study—to assess the pulmonary emboli. “It is very interesting to see there is no match between the extension of the pulmonary embolus and the pulmonary perfusion abnormality,” he explains.

In one particularly interesting case at the university Hospital of Rouen, pulmonary embolus was suspected in a patient presenting with chest pain. Prof. Dacher performed a GSI study and discovered the pulmonary artery was encased by a tumor.

“The flow was limited and there was hypo perfusion that was completely obvious on the GSI study because we could see the anatomy and function,” he explains. “If we had performed only scintigraphy—historically the exam of choice for these cases—we would have only noted the reduced perfusion of the upper lobe.” This could have resulted in an incorrect diagnosis of pulmonary embolism and possibly led to the patient unnecessarily receiving an anticoagulant, he explains.

Valentin Sinitsyn, MD, PhD, is Chief of the Radiology Department at the Federal Center of Medicine and Rehabilitation (Moscow, Russia) and Professor and Chair of Radiology, School of Fundamental Medicine at Moscow State university. Prof. Sinitsyn is also the elected President of the Russian National Congress of Radiology 2011; Vice-President of the European Society of Cardiac Radiology; and a member of the ECR Program Planning Committee. His interests include cardiovascular imaging, MR, contrast media, education, and internet and computer applications in radiology. Prof. Sinitsyn has authored and co-authored more than 110 articles and eight books on radiology and internet applications, edited Russian versions of two international textbooks on MRI and CT, and serves on the editorial boards of the International Journal of Cardiovascular Imaging, the Journal of Cardiovascular Magnetic Resonance, Diagnostic Imaging (Europe) and Imaging Decisions.

Prof. Valentin Sinitsyn

About the facility

The Federal Center of Medicine and Rehabilitation (Moscow) is well known as a modern surgical hospital specializing in high-tech neurosurgery, abdominal surgery, gynecology, orthopedics, and sports injury rehabilitation. The Department of Radiology performs all radiological examinations, including CT, MR, and nuclear scans, around-the-clock as needed. It is also focused on scientific research regarding new imaging technologies and contrast media agents. As an academic hospital, the Center offers residency and postgraduate programs as well as clinical faculty positions in the School of Fundamental Medicine at Moscow State university. The first-in-Russia Discovery CT750 HD scanner was installed here in November 2009. Figure 1A. A GSI iodine map depicts a wedge-shaped

perfusion defect in the 9th segment of the left lung.Figure 1B. A small embolus inside the corresponding segmental branch of the left pulmonary artery can be seen with GSI.

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Oncology

For Prof. zhang, the most significant use of spectral CT is to quantitatively characterize lesions via the spectral Hu curve, which graphically displays the attenuation characteristic of a region across all 101 spectral energies.

“using the monochromatic images, we can visualize anatomic and internal structures of lesions, which is important for early detection.” says Prof. zhang. He finds the material characterization and quantification very useful in helping him identify different types of lesions and diseases, and gaining information on cancer at different stages.

Additionally, GSI provides rich and reliable hemodynamic information of tissue with iodine quantification. “It helps us accurately identify infiltrated areas with the iodine-based images,” adds Prof. zhang, “and with a reliable method to evaluate hemodynamic status, we can evaluate therapy results more confidently.”

Lymphoma

Figure 2A. Affected lymph node of the neck.

Figure 2C. Affected lymph node of the mediastina.

Figure 2B. Affected lymph node of the porta pulmonis.

Figure 2D. Affected node of the spleen.

“GSI is not simply a new study area, rather it is changing the way we think and practice CT imaging.”

– Prof. Xiao-Peng Zhang

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Xiao-Peng zhang, MD, is the Professor of Radiology, Peking university Health Science Center, and Chairman of Radiology Department, Peking university Cancer Hospital and Institute. Prof. zhang also holds the positions of Chairman of oncology Imaging Committee, China Anti-Cancer Association; Managing Editor, Chinese Journal of Medical Imaging Technology; and Editor of the Chinese Journal of Radiology, Chinese Journal of Clinical oncology, and Chinese Journal of Practical Surgery. He authored three radiology textbooks and more than 80 research papers globally. Prof. zhang’s research interests include abdominal and thoracic oncology imaging for the early detection, accurate staging, and therapy evaluation of cancer.

Prof. Xiao-Peng Zhang

In the Radiology Department of Peking university Cancer Hospital and Institute, a GSI team of 20 experienced radiologists and researchers, led by Professor Xiao-Peng zhang, has conducted more than 1,500 routine GSI scans and 20 pilot studies in the first three months of using GSI. They have achieved numerous promising results, submitted 30 research abstracts and 15 research papers to prominent journals of radiology.

one clinical question that a traditional CT exam cannot answer is whether or not a lesion enhances. This is often evaluated in terms of Hounsfield units, explains Prof. Sinitsyn. Yet the value assigned may not be precise, as the enhancement may be partially due to beam hardening artifact or artificially inflated via image processing.

“When I see a small enhancement, I may not be able to determine if it is true or artificial,” he says. “By comparing water and iodine images, I get the information to quantify the area of interest based on the accumulation of iodine and objectively determine if the lesion is a concern that requires follow-up.”

Renal stones

Prof. Sinitsyn also uses GSI to assess renal stones. often, where there is one kidney stone, there are more, so it is important to know the material composition. “GSI can help quantify the renal stone, whether it is a calcified stone or predominantly a soft stone containing uric acid,” he says. The latter can be treated with techniques other than surgery, Prof. Sinitsyn adds.

Figure 3. Spectral Hu curves show the same pattern of different affected lymph nodes in the same patient with lymphoma, which indicate these lymph nodes are of the same nature as lymphoma.

About the facility

Peking university Cancer Hospital and Institute is one of China’s most-respected centers dedicated exclusively to cancer patient care, research, education, and prevention. Each year, more than 300,000 patients turn to the institute for cancer care in the form of surgery, chemotherapy, radiation therapy, immunotherapy, or combinations of these and other treatments.

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Figure 4. Note the lack of metal artifact in patient with spinal instrumentation in the 110 keV image on the right compared to the 70 keV image on the left.

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Reducing artifact

With the continued increase in metal instrumentation—hip and knee prosthesis and spinal fusion, for example—the issue of artifact degrading image quality is becoming more pronounced, explains Dr. Tanenbaum. Reducing these artifacts is an important benefit that GSI provides in his daily practice.

“Between 33% and 40% of our routine spine exams involve instrumentation,” he says.


name of author

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Traditional techniques are challenged by implanted metal hardware, leading to images with beam hardening and streak artifacts.

“Spectral CT generates virtually pristine images in these most challenging circumstances where traditional techniques often fail,” Dr. Tanenbaum adds. “We can restore the information in areas that were previously deteriorated by artifact and thus, substantially improve the imaging results in these difficult cases.”

Recently at the European Congress of Radiology (ECR) 2011 annual meeting, Prof. Dacher presented a study demonstrating that he could more easily obtain high quality images of the femoral arteries in patients with metallic hip prosthesis by using GSI. “We cannot accept limitations in the investigation of the femoral artery, so this may be a strong advantage of GSI.”

Enhancing contrast resolution

Iodine-based contrast material used in CT imaging is very well suited to being manipulated—either enhanced or eliminated, explains Dr. Tanenbaum. “Not only can we make the iodine more useful, but it provides an opportunity to deal with sub-optimal contrast administration,” he adds.

Radiologists can either make the contrast more conspicuous in the image by adjusting the energy or create a material-based image that eliminates visibility of the contrast.

“With this capability, we have additional information in situations where, historically, we’ve performed both a non-contrast and post-contrast CT study,” Dr. Tanenbaum adds.

Prof. Dacher also sees an opportunity to use GSI in cases where optimal opacification (contrast enhancement) is not ideal, particularly in older patients or those without good venous access. “When we acquire images with GSI, it is possible to decrease keV and enhance the small amount of contrast media in the patient vessel.”

“Spectral CT generates virtually pristine images in these most challenging circumstances where traditional techniques often fail.”

– Dr. Lawrence Tanenbaum

Dr. Lawrence Tanenbaum

Lawrence N. Tanenbaum, MD, FACR, is Director of MRI, CT, and outpatient/Advanced Development, Mount Sinai School of Medicine (MSSM). The school opened its doors in the fall of 1968 and has since become one of the world’s foremost centers for medical and scientific training. Located in Manhattan, MSSM works in tandem with The Mount Sinai Hospital to facilitate the rapid transfer of research developments to patient care and clinical insights back to the laboratory for further investigation.

About the facility

Mount Sinai Medical Center, named to u.S. News & World Report’s 2009-2010 Best Hospitals Honor Roll and ranked 19th nationally, treats nearly 47,000 inpatients and 427,000 outpatients each year. Renowned for its spinal cord and brain injury rehabilitation, Mount Sinai was the first medical school to establish a Department of Geriatrics, as well as departments of environmental and occupational medicine. With more than 3,000 full-time and voluntary physicians on staff, the hospital is a regional leader in numerous specialties and the world’s only center for the diagnosis and care of Jewish genetic diseases.



Figure 6. GSI helps reduce artifact and provides a diagnostic-quality study even in the presence of metal instrumentation. The GSI image on the right at 70 keV plus MAR clearly demonstrates the reduction in artifact versus the 140 kVp image on the left.

“We cannot accept limitations in the investigation of the femoral artery, so this may be a strong advantage of GSI.”

– Prof. Jean-Nicolas Dacher

Figure 5. 3D reconstructed image on left at 140 kVp demonstrates lack of imaging data due to artifact from metal instrumentation. Note the GSI image (right) at 70 keV plus MAR ( metal artifact reduction) clearly depicts the right femoral artery even in the presence of metal.

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Changing clinical pathways

Within one year of using GSI at the university Hospital of Rouen, Prof. Dacher and his colleagues have changed their clinical protocols. “For pulmonary embolisms, metallic prosthesis, and pulmonary hypertension cases, we first utilize CT with GSI,” he says.

“In lung perfusion, we have replaced scintigraphy—and in some cases MRA—with a spectral CT exam.” The advantage of CT, he adds, is the speed of the exam and relative patient comfort—both important considerations when evaluating very ill or elderly patients.

“What really impresses me,” Prof. Dacher says, “is the ability to quantify the amount of iodine within a voxel. This is a technical breakthrough that will continue to become more important in medicine.”

At Mt. Sinai, GSI is now a routine study on patients with instrumented spines or in neuroradiology cases when the radiologist suspects the presence of an aneurysm clip. “Spectral CT improves the quality of some of our most challenging exams,” Dr. Tanenbaum says, “and it certainly has an impact on the information I can provide for surgical planning purposes.”

The additional information generated by GSI “helps with deciding the course of treatment for the individual patient, in particular whether it should be more conservative or aggressive,” explains Prof. Sinitsyn. He sees the potential to eliminate additional studies with the ability to quantify areas of interest while providing an objective and accurate diagnosis.

“Dual-energy will further increase the significance of CT, including when and where we use it,” he adds. It is his hope that the continued use of spectral CT will enable the implementation of an objective, quantitative measurement of CT data—in other words, moving away from Hounsfield units to the use of effective atomic numbers or something similar.

Driven by an RSNA initiative, the aim of the radiology community is seeking to be more quantitative in imaging, explains Dr. Tanenbaum. Leveraging this capability of spectral CT should impact positively in the characterization of disease and be useful for surveillance of patients. “It clearly gives us rich, more quantitative information than we had before,” explains Dr. Tanenbaum. “We are only touching the surface of future possibilities—it remains to be seen with widespread implementation and clinical imagination where spectral CT will lead us.”

What it really comes down to is whether spectral CT will raise the level of diagnostic confidence and reduce the reliance on multi-modality testing resulting from inconclusive exams.

“GSI is not simply a new study area. Rather, it is changing the way we think and practice CT imaging,” adds Prof. zhang. “It advances CT to an entirely new level and opens up a brave new world for the pioneer who embraces the spirit of discovery.”n

Prof. Jean-Nicolas Dacher

Jean-Nicolas Dacher, MD, PhD, is a Professor of Radiology and Diagnostic Imaging and the Chief of the Department of Diagnostic Imaging at Rouen university Hospital. After studying medicine in Caen, France, he completed his residency in Diagnostic Imaging and Radiology at Rouen university. Prof. Dacher was a research fellow at the Free university of Brussels, Harvard Medical School (the Sachs Foundation Award) (Boston), and the university of Sherbrooke (Quebec, Canada). He has received an award from the Société Française de Radiologie and authored more than 130 articles and several book chapters in French and English textbooks. Prof. Dacher’s areas of interest include non-invasive cardiovascular imaging (MR and CT) in children and adults and MR functional imaging of the kidneys.

About the facility

The university Hospital of Rouen is located in a city of 400,000 inhabitants made famous by the martyrdom of Joan of Arc in 1431, its Gothic Style Cathedral, and many paintings by Claude Monet. This 2,500 bed hospital in Northwest France is a full-service, multi-specialty facility that counts among its major innovations the invention of the transarterial aortic valve replacement (TAVI) by Alain Cribier, MD, Chief of the Department of Cardiology and a worldwide renowned cardiologist who implanted the first patient in Rouen in 2002. It is through the Departments of Cardiology and Cardiac Surgery and the Laboratory of Cardiovascular Pharmacology (INSERM 644) that the hospital developed a dynamic clinical and research cardiac imaging unit utilizing MDCT, MRI, and echocardiography.

Continuing enhancements to GSI

Thanks to the collaboration of clinical leaders such as Prof. Dacher, Prof. Sinitsyn, Dr. Tanenbaum, and Prof. zhang, GE Healthcare continues to refine GSI. Although Prof. Dacher has limited experience with the next iteration of GSI Viewer, he notes that it provides faster reconstruction speed and the ability to generate MIPs and MPRs. Both Prof. Dacher and Prof. zhang see the potential to further reduce patient exposure to dose, leading to greater utilization of the technique.


C L I N I C A L V A L u E L o W D o S E C T I M A G I N G

Introduction

We explored new methods that offer significant dose reductions, specifically the new reconstruction-based dose reduction technique, ASiR.**

Historically, common methods for achieving dose reduction were Automated Exposure Control and dedicated procedure-based protocols with low techniques for pediatric imaging, and ECG modulated mA and BMI-based for cardiac imaging. However, these dose reduction methods are based on regulated and modulated use of mA.

Another method involves improving the image quality at lower mA values. This can be achieved by using softer reconstruction kernels, or by using post reconstruction image softening filters. Yet, these image space-based filter techniques do not assure any kind of dose reduction to the patient as they are applied post scanning.

Filtered Back Projection (FBP) has been used as the reconstruction method for 30 years. This closed form of reconstruction involves projection based data collection, filtration, back projection, and weighting. Yet, it is based on several assumptions and does not account for all physical parameters such as detector shape, focal spot size, image voxel size, and photon flux variation between projections being transmitted from the patient’s body. Thus FBP provides a calibrated, filtered image that undergoes many assumptions.

ASiR is an IR technology that focuses on the modeling of the noise properties which may enable noise in the reconstructed image and may allow for lower dose examinations even in large patients or studies requiring thinner slices. In routine imaging exams at our hospital, 40% to 50% ASiR is used consistently.

Making Reliable Low-dose CT a Clinical RealityBy Ramakrishnan RS, MD, DNB, Consultant Radiologist1; George Joseph, MD, DMRD, Consultant Radiologist2; and Sundar RK, BSc, DRT, DAMIT, Clinical Applications Manager3

1MedALL Healthcare Pvt. Ltd. 2Lakeshore Hospital and Research Centre3GE Healthcare

ASiR* is an iterative reconstruction (IR) technique that focuses on the modeling of the noise properties which may enable noise reduction; as measured by pixel noise standard deviation in the reconstructed image and may allow for lower dose examinations even in large patients or studies requiring thinner slices.

** In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task.


C L I N I C A L V A L u EL o W D o S E C T I M A G I N G

Dr. Ramakrishnan RS

Ramakrishnan RS, MD, DNB, is a Consultant Radiologist at MedALL Health Care Pvt. Limited and Malar Fortis Hospitals. He received his degrees from Kilpauk Medical College and Sri Ramachandra Medical College & Research Institute. Dr. Krishnan completed a fellowship in cardiac MRI at Sankt Gertrauden Krakenhaus (Berlin). His areas of interest are body imaging, cardiac CT, and MRI.

Dr. George Joseph

George Joseph, MD, DMRD, is Chief Radiology Consultant at Lakeshore Hospital and Research Centre, Lissie Hospital, and Lourdes Hospital at Cochin, Kerala. Dr. Joseph received his MBBS from Government Medical College Kottayam and medical degree in Radio-diagnosis from Government Medical College Trivandrum. He was one of the first radiologists trained on a CT scanner at Sir Gangaram Hospital Delhi. Today, his primary interests in CT imaging are abdominal imaging and image-guided interventions.

Sundar RK

Sundar RK, BSc, DRT, DAMIT, Clinical Applications Manager, GE Healthcare

C L I N I C A L V A L u E

Routine imaging

ASiR may enable improvement to the Low Contrast Detectability (LCD). Following are several patient cases demonstrating the value of using ASiR in our facility.

Case 1An abdomen study performed with 40% ASiR maintains image quality by reducing noise and dose (Figure 1). Note the improved visualization of contrast-enhanced structures. In this study, the total dose delivered is 3.35 mSv (obtained by EuR-16262 EN, adult abdomen factor of 0.015 x DLP).

Figure 1. Abdomen study with dose of 3.35 mSv using 40% ASiR in the bottom image. Note the improved visualization of contrast-enhanced structures compared to the top image.



Figure 3. 3D volume-rendered image (left) shows cerebral circulation and the positioning of the aneurysm clips. The MPVR image with MIP (center) clearly demonstrates the vasculature even in the presence of high dense metal clips. The 3D image of the clip by itself (right) depicts the clip deployment without any streak artifact.

We have also used ASiR to scan dense objects such as metallic surgical sutures, and implants. We have been very pleased with the visualization realized in these challenging cases.

Case 3Follow-up CTA of patient post-cerebral aneurysm surgery. With 50% ASiR at 76 mAs, the effective dose was 3.1 mSv (obtained by EuR-16262 EN adult head factor of 0.0023 x DLP).

Case 2Routine chest scan conducted with 50% ASiR at 24 mAs yielded a total dose of just 0.72 mSv (obtained by EuR-16262 EN adult chest factor of 0.017 x DLP).

Figure 2. 3D volume-rendered image (right) shows air way tree with transparency model of the lungs.


C L I N I C A L V A L u EL o W D o S E C T I M A G I N G

Coronary CTA

In our experience, the combined use of ASiR with Snapshot* Pulse—prospective gated scans with adaptive gating—has further reduced radiation dose by 80%, for an effective dose of 1 mSv and lower, in some cases.

Case 481 year-old male patient presented with angina on exertion. The study showed atheromatus calcified plaque in all three vessels with mild to moderate luminal narrowing. SnapShot Pulse technique was used along with 40% ASiR. The heart rate was unstable and a dynamic padding of 25 mS was given. The DLP of the study was 77.87 mGy.cm, and the effective dose is 1.09 mSv (EDLP, ICRP chest factor 0.014).

About the facility

Lakeshore Hospital and Research Center is a multi-specialty hospital aimed at bringing international standards in healthcare to Kerala. Lakeshore Gastro Intestinal Surgery unit is used as a training center for FRCS examinations by the Royal College of Surgeons (Edinburgh). Lakeshore oncology Department carried out bone marrow transplantation and peripheral stem cell transplantation for blood cancer patients for the first time in the history of private hospitals in Kerala. The hospital was the first to introduce the artificial insulin pump for diabetes patients in South India.

Figure 4. (A) 3D Volume Rendered image, (B) LAD Curved view demonstrates dense calcification along the coronary artery wall, and (C) the blue vertical block on the ECG shows the prospective triggering and exposure in the diastolic window.

About the facility

MedALL is a leading chain of diagnostic and imaging centers across South India. MedALL was started with a vision to provide diagnostic services and endeavors to touch, serve and solve health-related challenges of its customers and to provide high level of diagnostic confidence to referral physicians. MedALL has earned a reputation among referral physicians and customers for providing the highest levels of customer satisfaction with sheer excellence and dedication in the quality of diagnostic services. MedALL started its journey by acquiring some of the leading diagnostic centers such as Precision Diagnostics in Chennai and Clumax Diagnostics in Bangalore. MedALL currently operates diagnostic centers in Bangalore, Chennai, Trichy, Tirunelveli, Melur, Pudukottai, Rajapalayam, Kurnool, Kakinada, and Vizag.

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Whole body scan, poly trauma application

A single CT whole body trauma evaluation is one of the most powerful tools for managing patients with multiple critical injuries. Yet, the dose has always been a consideration. This led to conducting whole-body scans on a limited basis and only for specific regions to reduce radiation exposure to the patient. With the advent of ASiR, however, we are doing our poly-trauma imaging with lower doses.

Case 5 Medium-sized male patient fell from elevated height. Initial head scan showed intracranial hemorrhage and patient was sent to surgery. Patient was also referred for a whole body scan to evaluate the strong suspicion of internal organ injury and spinal fractures. using 40% ASiR, the total whole body dose as integrated with different regional weighting factors was 3.29 mSv (Each region’s dose was calculated using EuR-16262 EN with adult factors of 0.0023 for head, 0.0054 for neck, 0.017 for chest, 0.015 for abdomen and 0.019 for pelvis).

Conclusion

ASiR is an alternative reconstruction technology where the system statistics are modeled. This may enable a reduction in pixel noise standard deviation hence allowing for reduced mA and thereby dose.

ASiR was designed with dose reduction and LCD improvement in mind. In our experience, the selected ASiR level correlates, to some extent, with the dose reduction in our department. For routine imaging, we use 40% to 50% ASiR.

At MedALL Healthcare and Lakeshore Hospital and Research Centre, we have found the benefits associated with lower radiation dose derived with ASiR are so encouraging that we are now using the technique for all CT scans, anatomies, and routine imaging studies. Today in our facility, the ability to image gently has become a reality with the use of ASiR. n

Figure 5. The whole-body, contrast-enhanced scan was completed in 8 sec with 0.625 mm thin slices.

GE HealthcareComputed Tomography

© 2011 General Electric Company *Trademark of General Electric Company.

No company has done more to bring low dose to patients than GE Healthcare. That’s no coincidence — in fact, it speaks to the single purpose that guides our business: helping you deliver high-performance care.

Our approach is built upon a foundation of low-dose technology. But it also encompasses the best practices and industry exposure we’ve amassed for decades. The result is a true end-to-end partnership designed to help you provide lower dose patient care, more efficiently, and more effectively.

You’re here to deliver high-performance care. We’re here to help you do it.

www.gehealthcare.com/LowDoseCT

GREAT CARE BY DESIGN.

PartnershipDecades of CT experience have made us a strong, dedicated partner who understands healthcare’s complexities

ASiR*

Lower image noise while improving low contrast

detectability and image quality.

Gemstone* Spectral ImagingExpand information for clinical

diagnosis and workflow.


C L I N I C A L V A L u E E D I M A G I N GC L I N I C A L V A L u E

Convincing evidence exists to validate the use of coronary CT angiography (CTA) to triage patients presenting with chest pain to the Emergency Department (ED).1 Yet, creating a successful chest pain triage program requires more than just implementing technology. It should involve developing new protocols and fostering collaboration between clinical specialties to successfully change patient management and outcomes.

At Baptist Hospital of Miami, Ricardo C. Cury, MD, FSCCT, Chairman and CEo of Radiology Associates of South Florida and Director of Cardiac Imaging at Baptist Hospital, and his colleagues have implemented ED chest pain protocols, including the use of CTA. These protocols have helped to decrease length of stay and the cost of care and improve clinical outcomes. The target for the ED, he says, is to quickly assess patients with a low probability of acute coronary syndrome.

This was no easy task. Baptist Hospital has a 100-bed ED and sees an average of 25 patients each day presenting with chest pain. In the ED, 10 CTAs are performed daily on a LightSpeed* VCT.

In addition to having the right technology, Dr. Cury explains, it is important to implement and integrate the CTA protocol—developed in conjunction with ED clinicians, hospitalists, radiology, cardiology and administration—into the patient care process.

“Collaboration across specialties and gaining administrative support are the major drivers for success,” he says. “We held several meetings with these groups to define the protocols—and this is very important so everyone supports and follows them.”

CTA Changing Patient Management in the ED


C L I N I C A L V A L u EE D I M A G I N G C L I N I C A L V A L u E

CTA drives successful patient management

Baptist Hospital’s chest pain protocol for the use of CTA defines five levels of care based on clinical presentation, ECG, and cardiac enzymes (Table 1). Patient management is determined by the degree of coronary stenosis detected by CTA.1 Patients without stenosis are discharged to follow up with their primary care physician. Those with mild, non-obstructive stenosis of less than 50% are discharged from the ED and referred for consultation with a cardiologist or primary care physician within one week to ensure proper treatment. In patients with moderate stenosis (50% to 70%), a stress MPI or cardiac catheterization with fractional flow reserve is conducted to determine hemodynamic significance of the lesion. Patients with severe stenosis, graded at 70% or greater are sent to the cardiac cath lab for further diagnosis and possible intervention.

The implementation of a coordinated protocol for chest pain patients using CTA at Baptist Hospital has led to several remarkable results, based on the preliminary experience of over 500 patients.

“using this protocol, we are able to significantly decrease downstream testing after CTA,” says Dr. Cury, “because 85% of patients could be discharged right away, including those with negative and mild non-obstructive disease.”

“After implementing the protocol, we experienced a 50% reduction in length of stay that is a direct result of decreasing patient work-up,” he continues. “When compared to our historical data, the direct reduction in healthcare costs after implementing the CTA protocol is $1,000 per patient.”

The number of major cardiac events (MACE) is also impressive at 0.1% at 30 days, well below the national average found in the literature of 2% to 4%, notes Dr. Cury.

CTA Chest Pain Protocol – Baptist Hospital

Patient with STEMI or new LBBB with ischemic symptoms. For these patients, door to balloon time is within 90 minutes.

Patients with non-STEMI or unstable angina, typical anginal symptoms with ST-segment depression, ischemic T-wave inversion. CHF or hemodynamic instability with chest pain. Patients are sent to the cath lab within 24 hours.

Patients with a moderate to high risk of ACS, a TIMI score greater than two, atypical chest pain or angina lasting less than 20 minutes, and negative cardiac enzymes and either negative or non-diagnostic EKG. Patients receive a SPECT MPI.

Patients with a low risk of ACS, a TIMI score of less than two, atypical chest pain or angina lasting less than 20 minutes, and negative cardiac enzymes and either negative or non-diagnostic EKG. These patients receive a coronary CTA for detection of coronary stenosis.

Patients with non-cardiac chest pain. Patients are triaged with a chest X-ray, chest CTA (PE, Aortic Dissection or TRo), ventilation / perfusion scan or GI work-up, depending upon suspected pathology.

Group 1.

Group 2.

Group 3.

Group 4.

Group 5.

CTA Changing Patient Management in the ED

“using this protocol, we are able to significantly decrease downstream testing after CTA because 85% of patients

could be discharged right away, including those with negative and mild non-obstructive disease.”

– Dr. Ricardo Cury


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References1 Cury RC, Feuchtner G, Mascioli C, et al. Cardiac CT in the emergency department: Convincing evidence, but cautious implementation. J Nucl Cardiol 2011;18:331–41.

Dr. Ricardo Cury

Ricardo Cury, MD, FSCCT, is the Chairman and Chief Executive officer of Radiology Associates of South Florida, the tenth largest Radiology private practice group in the united States. He is also a non-invasive cardiovascular radiologist and Director of Cardiac Imaging at Baptist Hospital of Miami and Baptist Cardiac & Vascular Institute, and a Clinical Associate Professor at Florida International university. Dr. Cury has interpreted more than 10,000 Coronary CT angiograms and more than 5,000 Cardiac MRI scans.

Dr. Cury received his doctorate degree from Santos School of Medical Sciences in Brazil and finished his residency in Diagnostic Radiology at MedImagem, Beneficencia Portuguesa Hospital. He completed a Clinical/Research Fellowship in Cardiovascular Imaging at Massachusetts General Hospital/Harvard Medical School. Dr. Cury won the young investigator award sponsored by the American Heart Association, Radiology Council, during the North America Society of Cardiac Imaging (NASCI) in 2002.

Dr. Cury is author of more than 100 original scientific publications in major radiology and cardiology journals and over 200 abstracts, book chapters, case reports, or invited presentations. He has been the principal investigator in four research grants. He is an associate editor of the Journal of Cardiovascular CT and a reviewer of several journals including Circulation and JACC.

The right technology

The LightSpeed VCT features GE’s ASiR* (Adaptive Statistical Iterative Reconstruction) technology which may enable dose reduction. “We routinely use SnapShot* Pulse (a prospective gating feature), ASiR, mA range of 250 to 500, and 100 kV to acquire images with an average of 1 millisievert on patients under the age of 65 with a BMI of less than 25,” he adds.

Before implementing ASiR, the average dose was 5 mSv for all patients. “Radiation dose reduction while maintaining image quality§ with ASiR is a key component in this protocol,” Dr. Cury says, “particularly as we look at lifetime dose for patients who received multiple CTAs.**”

Patients with heart rates over 60 bpm are given an oral beta blocker—100 mg Po—in the ED as soon as they are identified as a candidate for CTA, Dr. Cury explains. “This is very important as it improves workflow and alleviates the need for an IV beta blocker,” he says. However, if the heart rate remains high, they can still administer the IV beta blocker in the CT room.

using the AW Workstation, vessels are delineated via an automated post-processing capability with additional processing completed by dedicated technologists. Images are available approximately 15 minutes after completing the case, and in most instances, the report is completed within one hour.

Dr. Cury understands why Baptist Hospital has been successful in implementing CTA in the ED while other facilities have struggled to improve outcomes while simultaneously reducing length of stay and the cost of care. “Coordination of care between specialties, including their buy-in to follow the protocol before patient presentation,” he says, “and having the right technology that provides good image quality and a dose reduction strategy, are all very important contributors to our success.” He recommends that as facilities look to the future, any investment in CT technology must consider both the image quality and dose performance of the system. n

§As measured by noise standard deviation.


“Radiation dose reduction while maintaining image quality§ with ASiR is a key component in this protocol, particularly as we look at lifetime dose for patients who received multiple CTAs.”



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About the facility

Baptist Health South Florida is the largest faith-based, not-for-profit healthcare organization in South Florida. Baptist Hospital of Miami Emergency Department is one of the largest in the united States. The new 67,000-square-foot ED is home to the second busiest emergency center in South Florida, treating more than 80,000 patients each year. The new Center has a total of 100 exam rooms, 20 of which are part of the new Children’s Emergency Center. Included are six state-of-the-art trauma rooms (four trauma rooms for adult patients, and two for pediatric patients) equipped with sophisticated technology to manage the most severe injuries. The new ER is designed to maximize space, visibility and flexibility while providing more comfortable, spacious treatment areas for patients and their families.

Radiology Associates of South Florida (RASF) has served residents of Miami-Dade County since 1968. The practice is the tenth largest private practice group in the uS and provides diagnostic radiology and interventional radiology/vascular surgery services to patients with many types of health conditions. RASF is affiliated with five hospitals and 12 imaging centers.

Figure 1A. A 62-year-old male presented with chest pain to the emergency department. His ECG and cardiac enzymes were negative. The low-dose coronary CT angiography demonstrates a significant stenosis in the proximal LAD (>90%) with non-calcified plaque.

Figure 1B. In same patient, invasive coronary angiography confirms the presence of a high-grade stenosis in the proximal LAD (95%). Patient underwent PCI with stent placement in the proximal LAD.

“Coordination of care between specialties, including their buy-in to follow the protocol before patient presentation and having the right technology that provides good image quality and a dose reduction strategy, are all very important contributors to our success.”



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Nestled near the Indian ocean is the Island of Mombasa, home to Kenya’s second largest city and its largest port. A diverse city, Mombasa traces its culture to Portuguese, Arab, and British settlers, as well as the native Swahili people.

The Nyali Bridge connects Mombasa Island to the northern mainland. It is in this North Coast area where residents can find quality, personalized healthcare at Jocham Hospital that is “mwananchi” friendly—it bridges the gap between high- and low-cost hospitals, yet offers a wide variety of services, including X-ray, ultrasound, and CT imaging.

“We provide affordable medical care to people who cannot pay for the care from the high cost institutions,” says Peter umara, MD, Lead Radiologist of Jocham Hospital. Yet, providing lower cost services doesn’t translate to a lack of services or quality care. In November 2004, the hospital delivered the tiniest surviving baby in Kenya, a 1.4 lb, 5.9 inches boy born with complications at 28 weeks gestation.

Fulfilling a need

Providing access to advanced imaging equipment is half the challenge at Jocham Hospital. Having a reliable, modern system is the other.

At Jocham, CT imaging needs center around routine studies for several reasons. First, the cost to purchase, install, and maintain today’s most advanced multi-slice CT scanners is prohibitive in a market such as Mombasa. Second, the aim is to provide access to imaging services for as many residents as possible—basic healthcare is in greater demand than specialty services. Third, the cost of technology directly impacts the cost that Jocham charges for medical services.

So when Dr. umara and his colleagues wanted to replace an old CT scanner that was often not working more than it was running, they knew the choice had to be a reliable, lower cost scanner. However, they did not want to purchase an older, used system that may compromise image quality and functionality.

Enter the Brivo* CT325§. Designed to extend quality care to more people, the Brivo CT325 is a new, ultra-compact CT system with a simple interface, new table, and gantry that help streamline CT exam workflow and increase patient throughput. With advanced GE Healthcare technologies inside, the system has the ability to provide excellent image quality at low dose.

“Brivo CT325 helps us extend healthcare to more people who would otherwise not have access to it,” says Dr. umara. “our patients are not too well off financially, yet the physicians need our services and diagnosis to provide better treatment.” With the Brivo CT325, Jocham Hospital now has capability to do both.

Lowering cost. Increasing access. These are two pillars of the healthymagination initiative from GE Healthcare. While Brivo CT325 was expected to deliver both to facilities worldwide, it has also resulted in helping Jocham increase the breadth of CT imaging services.

Kenya Hospital Extends Quality CT Imaging to More Residents


Sub millimeter slice of the ear

“Brivo CT325 helps us extend healthcare to more people who would otherwise not have access to it.”

– Dr. Peter Umara

3D Volume Rendering Lumbar Spine


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“We are getting new requests for different exams, especially CT studies of the neck,” adds Dr. umara. He has also seen a general increase in patient volume, with many patients returning and selecting Jocham Hospital as their preferred healthcare provider.

The Brivo CT325 delivers on two important aspects, Dr. umara explains. “The system’s main strengths are the image clarity in routine exams and durability,” he says.

“We often conduct 15 scans each day and the machine continues to operate well without any issue.”

He also notes the system is user-friendly and has helped create a more efficient workflow. Their busy days aren’t compounded by technical or operational issues with the new CT system.

“This is the ideal system for clinics where general scanning is the primary imaging order each day,” Dr. umara says. “It is affordable and has a very small footprint— for other facilities like ours, it is the type of CT scanner they should go for.” n

About the facility

Jocham Hospital is located on the North Coast of Mombasa Island. Since opening its doors on May 5, 1999, Jocham Hospital has served patients in a “mwananchi” friendly way by bridging the gap between higher cost hospitals and basic health facilities with quality, personalized healthcare at an affordable rate for the local residents. The hospital offers a range of services, from outpatient care to surgical suites to advanced imaging services such as X-ray, ultrasound, and the Brivo CT325 system.

Brain study

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Chest image

“The system’s main strengths are the image clarity in routine exams and durability.”

– Dr. Peter Umara

Dr. Peter Umara

Dr. Peter umara Marenya is the Lead Radiologist at Jocham Hospital, Mombasa, Kenya. His qualifications include MBchB, MMED Radiology university of Nairobi. Dr. umara has completed FRCR Part 1 and is to enroll for Part 2.

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Picture a world where CT dose is no longer a significant concern. Where clinicians can use CT to obtain more information about human anatomy and conduct every exam at 1 mSv or less. And, where clinicians and patients are confident that a routine CT exam will provide the detailed diagnostic information at currently unheard of doses.

Picture that world taking the first step to emerging today.

Veo*§ is the amazing advance from GE Healthcare in CT model-based image reconstruction that has enabled clinicians to achieve a remarkable breakthrough in ultra-low dose for CT imaging.** Several clinicians from around the world have experienced the ultra-low dose and high image quality capabilities of Veo and believe this reconstruction technique may enable a breakthrough in low-dose imaging.

The Discovery* CT750 HD is the first GE system with this new game-changing technology. The university Hospital, Brussels, was also one of the first clinical sites worldwide to use Veo. Johan de Mey, MD, PhD, Chair of the Radiology Department, and Nico Buls, PhD, Radiation Physicist, began testing the reconstruction technique with a phantom to see how low they could get dose to go and still expect to be able to view the simulated anatomy and pathology.

“With a clinical chest CT at 0.05 millisieverts, we produced images where we could see and analyze pathology,” Prof. de Mey says. “Achieving that ultra-low dose with readable images was quite amazing.”

And while it already offers the dose-lowering technology ASiR* (Advanced Statistical Iterative Reconstruction), Kwek Boon Han, MBBS, FRCR, FAMS, radiologist with Asia HealthPartners (AHP) (Singapore) says, “With Veo, the image quality is outstanding even as the dose is dramatically lowered.” He explains that Veo takes into account the three-dimensional nature of the X-ray source, image voxel, and the detectors in the modeling of the final image rather than assuming these factors to be mere single-dimensional points in space.

“GE Healthcare has taken the leadership role in reducing radiation dose in CT, culminating in the ultra-low dose CT with Veo,” Dr. Kwek adds.

Changing imaging protocols

Long recognized for providing greater clarity and more detail than conventional X-ray exams, CT has changed the way clinicians diagnose disease and monitor patient treatment. Yet, the invaluable information CT provides has contributed to increased use and rising concerns over dose in recent years. Healthcare professionals, following ALARA principles, are required to take every reasonable effort to minimize exposure to ionizing radiation. Veo represents one of the most significant breakthroughs providing the ability for a step change in dose reduction.

Veo: A New Breakthrough is Re-writing the Rules of Low-dose CT Imaging

Figure 1. Veo images demonstrate high image quality at ultra-low dose of 0.05 mSv (obtained by EuR-16262 EN, using an adult chest factor of 0.017 DLP) for 26-year-old patient with cystic fibrosis. Acqusition parameters: 80 kV, 10 mA, 0.4 sec rotation. (Top) Veo coronal image with lung window width and window level settings. (Bottom) Volume rendering with segmentation of the lobes of the lungs and bronchi.

§Veo is 510(k) pending at FDA. Not available for sale in the united States.

** In clinical practice, the use of Veo may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task.

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The challenge of low-dose imaging is to perform a CT scan with the lowest possible dose that enables a clinical diagnosis, says Dr. Kwek. It’s a balance between noise levels that result from lower dose and image quality. So, he selected dose reductions that commensurate with the comfort level of the reporting radiologists.

“We perform CT studies with reduced radiation dose around 0.3 mSv for paranasal sinuses, 1 mSv for head, 0.5 mSv for thorax, 1.5 mSv for renal stone, 3 mSv for thorax, abdomen and pelvis, and 2.0 mSv for CT colonography, including prone and supine studies with intravenous contrast,” Dr. Kwek says.

The implications of ultra-low dose CT imaging are far reaching, particularly in pediatric imaging. “We would like to do more CT imaging of pediatrics and young adults, but they are more sensitive to issues of dose,” Prof. de Mey explains. While MR is an option for these young patients, he often finds the need to administer general anesthesia to obtain quality images in small children, primarily due to the fact the exam takes much longer than CT. For some patients, MR may not be suitable.

“With Veo, we can conduct lower dose CT scans in children, too, and this is particularly important in groups that require continued follow-up, such as those with cystic fibrosis or lymphoma,” Prof. de Mey says.

In fact, the hospital has changed its pediatric protocols—first considering using ultra-low dose with Veo for children receiving a CT study. According to Dr. Buls, the revised hospital’s pediatric protocols have resulted in lower pediatric doses.

“In two months we’ll review the patient data to see if we can continue to reduce dose in a step-by-step manner. Based on our phantom data, we believe we can achieve a further reduction in dose.”

At Keio university Hospital (Tokyo), Masahiro Jinzaki, MD, Assistant Professor in the Department of Diagnostic Radiology, is also impressed in the ability of Veo to reduce dose yet improve image clarity for routine studies.

“We have drastically reduced dose without any impact on image clarity,” he says. “Veo is completely different than any current dose lowering technique because we can reduce dose and maintain contrast noise ratios and spatial resolution.”

Jean-Louis Sablayrolles, MD, is a radiologist at Centre Cardiologique du Nord (CCN) in Saint-Denis, France, where he has been chief of the CT and MRI Department since 1988.

Dr. Jean-Louis Sablayrolles

About the facility

CCN is a private clinic created by a cardiology group in 1973 in Saint-Denis, North of Paris, France, that is dedicated to the treatment of cardiovascular pathologies. With more than 180 beds, CCN performs over 1,000 cardiac interventions each year and is considered one of the finest cardiovascular centers in the world. The facility has performed CT cardiac exams since March 2000 and acquired a Discovery* CT750 HD in July 2008.

About the facility

Located in the heart of Europe, the university Hospital Brussels is one of Belgium’s premier centers of excellence in healthcare, biomedical research and medical education. one of seven university Hospitals in Belgium, it is closely associated with the Brussels university. university Hospital Brussels has gained recognition at both a national and an international level. With its 700 beds and staff of 3,000, close to 30,000 inpatients and 500,000 outpatients are treated every year.

Johan de Mey, MD, PhD, is Chair of the Radiology Department at university Hospital, Brussels, and a Professor at Brussels university where he is also the coordinator for radiology resident training. Prof. de Mey earned both doctorate degrees at the Vrije universiteit Brussel; his PhD thesis was CT fluoroscopy in interventional radiology. As Professor, he lectures on radiology anatomy, normal and pathologic radiology and emergency radiology.

Prof. Johan de Mey

Figure 2. Abdomen pelvis CT with Veo on patient with Crohn’s Disease. Compared to the FBP images on left, note the significant noise reduction with the Veo image on the right, achieved with an ultra-low dose of 1.9 mSv** at 100 kVp (obtained by EuR-16262 EN, using an adult abdomen factor of 0.015 x DLP and an adult pelvis factor of 0.019 x DLP).

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Dr. Jinzaki also sees greater potential for implementing ultra-low dose studies, such as those used for lung studies, CT colonography, and CT urography. “With lower dose, we may be willing to replace more conventional X-ray studies to gain the greater information provided from CT.”

Jean-Louis Sablayrolles, MD, Chief of the CT and MRI Department at the Centre Cardiologique du Nord (CCN) (Saint-Denis, France), has been able to achieve his goal for common chest CT exams below 1 mSv. With the additional information gleaned from CT, the clinical value is compelling to Dr. Sablayrolles and he sees potential to replace current imaging methods with ultra-low dose chest CT using Veo in his practice.

“The impact of lowering dose, particularly for oncology and cardiovascular patients, is immeasurable,” he says. “If we are conducting follow-up exams every three or six months, it is very important to reduce the dose as much as possible.”

Greater image clarity

While lowering dose is a primary advantage of Veo, Dr. Sablayrolles also sees what he believes are significant image quality improvements.

“In oncology studies with Veo, we can also increase the conspicuity of the tumor for tissue characterization,” he explains. “In vascular studies, it is possible to differentiate stenosis from occlusion and reduce the blooming effect that results from the presence of a stent or calcified plaque.

“There are instances where a higher quality study is most important, and Veo enables us to increase spatial and contrast resolution to visualize very small lesions,” Dr. Sablayrolles adds.

At AHP, Dr. Kwek attributes greater image quality to the fundamental design of the Veo algorithm. “With Veo, there is improvement in the spatial resolution of tiny structures, such as the distal small airways in the patient,” (Figure 6).

Similarly, he attributes the ability to resolve small foci of calcification, particularly in patients with nephrocalcinosis, to Veo being able to accurately discriminate and separate the density of the image voxel.

Dr. Kwek Boon Han

Dr. Kwek Boon Han (MBBS, FRCR, FAMS) is a radiologist at Asia HealthPartners (AHP) (Singapore) since the centre was established in 2006. Prior to AHP, Dr. Kwek started the Heart and Vascular Center for AsiaMedic Limited in 2005. In 2003, Dr. Kwek completed a cardiac and chest research fellowship at Massachusetts General Hospital and Harvard under a government scholarship (HMDP). His primary clinical interests are in the applications of advanced CT and MRI imaging techniques.

About the facility

Asia HealthPartners Pte Ltd is a modern medical center in Singapore, conveniently located in the heart of orchard Road, which offers medical, surgical, and diagnostic imaging services. AHP is the training centre and luminary site of GE Healthcare, South-East Asia. Asia HealthPartners was awarded the “Reference Center for Advanced Imaging, GE Healthcare” as a commitment to deliver the latest in technology that enhances patient care as well as to provide advanced CT and MRI training for regional doctors. The imaging centre has been an early adopter of GE Healthcare CT technologies, including the LightSpeed* VCT in June 2006, the LightSpeed VCT XT in June 2007, the Discovery CT750 HD in December 2010, and Veo on April 2, 2011.

Figure 3. Vascular run-off study using Veo illustrates the image quality and lumen visualization improvement of popliteal stent compared to FBP technique. (A) FBP vessel tracking; (B) Veo vessel tracking; (C) FBP MIP vessel tracking; (D) Veo MIP vessel tracking.

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Benefits outweigh reconstruction time

As Veo uses a powerful new class of new reconstruction algorithms that more accurately model noise statistics, system optics, and radiation physics in the data acquisition process, it requires additional time to reconstruct images.

Even with extended reconstruction time, Prof. de Mey has been able to incorporate Veo into his facility without impacting workflow in the radiology department. As the scan is performed, the technologist has immediate access to images reconstructed with ASiR, and, there is no change in radiologist efficiency as the Veo reconstruction is completed in the background. Prof. de Mey uses the analogy of a blood test—it may take an hour for results, yet it doesn’t stop the provision of care or the flow of patients in the department. In his experience, the patient and diagnostic benefits from the ultra-low dose Veo exams justify the increase in reconstruction times.

Advances in computing power will continue to speed up the Veo reconstruction experienced by today’s pioneering users. “Veo has the potential to open new fields in CT imaging. We are only at the beginning of this new application and anticipate rapid advancement as typically seen in CT development,” adds Dr. Sablayrolles.

Nico Buls, PhD, is a medical physicist in medical sciences at university Hospital, Brussels. His research in medical imaging spans translational projects in medical imaging physics, radiation dosimetry, engineering, and diagnostic radiology. Dr. Buls has presented internationally and has authored one book chapter in an international textbook and more than 25 peer-reviewed articles.

Dr. Nico Buls

Figure 4. A 58-year-old female with left mastectomy for breast cancer currently undergoing chemotherapy. The CT scan was performed with DLP of 156.48 mGy cm.

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Figure 6. A 72-year-old male with inoperable lung cancer, currently undergoing chemotherapy. The distal small airway is better appreciated with the Veo (A) compared to the ASiR 50% image (B). The CT thorax and abdomen was performed with DLP of 108.25 mGy cm.

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Figure 5. A 38-year-old male known to have nephrocalcinosis, presenting with microscopic haematuria. The foci of faint calcification in the renal pyramids are apparent in the Veo image. The CT KuB (Kidney ureter Bladder) scan was performed with DLP of 118.79 mGy cm.

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Beyond comparison

The true power of Veo will be found in the ability to allow a lower dose examination while still delivering outstanding image clarity.

“Veo may enable a greater impact on dose than many other techniques,” Dr. Buls explains. “For example, adaptive collimation in spiral CT reduces dose by just a few percentage points. With Veo, we are seeing dose reduction of an entirely new order.” By developing dose reduction techniques via new reconstruction algorithms, GE Healthcare has opened up new possibilities for much greater dose savings.

Veo will impact how and when radiologists decide to utilize CT imaging. “A key concern with CT is the radiation dose; however, Veo may reduce that concern,” says Dr. Jinzaki. “There will be changes in the preference of CT imaging versus other exams, such as general radiography and MRI,” he explains.

Dr. Sablayrolles has no doubt that Veo will make a major difference in CT imaging. After three months experience with Veo, he has repeatedly demonstrated dose reduction and excellent image quality in study after study.

“We are at the beginning of a very interesting advancement in CT imaging,” says Dr. Sablayrolles, “and the future of Veo lies in every application. In my opinion, Veo is one of the major advancements in CT imaging—it is as important as the development of helical and multi-detector CT.” n

Dr. Masahiro Jinzaki

Masahiro Jinzaki, MD, PhD, is an Assistant Professor in the Department of Diagnostic Radiology at Keio university School of Medicine (Tokyo). He received both his medical degree, with honors, and post-doctoral degree from Keio university. Dr. Jinzaki has completed a research fellowship in the Department of Surgical Pathology at Keio university and in the Department of Radiology at Brigham and Women’s Hospital (Boston). He specializes in abdominal diagnostic imaging. Dr. Jinzaki also takes special interests and leads research in cardio-vascular and urology imaging. His experience with GE CT includes LightSpeed Plus, LightSpeed ultra, LightSpeed ultra16, and LightSpeed VCT. Dr. Jinzaki has been using Discovery CT750 HD since December 2008, and Veo since March 2011.

About the facility

Keio university Hospital was established by Yukichi Fukuzawa in 1858 and celebrated its 150th anniversary in 2008. In 1917, the medical school was launched as a medical preparatory course with Dr. Shibazaburo Kitazato, who became the university’s first dean, and three years later the university Hospital was opened. Today, the hospital has 27 diagnosis and treatment departments and 13 central treatment departments with over 800 clinical doctors (including resident physicians). An average of 4,000 patients walk through the hospital’s doors each day with approximately one-fourth hospitalized. on average, the Emergency Department treats over 20,000 patients and performs 13,000 operations each year.

Figure 7. Veo ultra-low dose chest CT conducted at 0.48 mSv (obtained by EuR-16262 EN, using an adult chest factor of 0.017 DLP) at 100 kVp. Veo coronal (top left); Veo fusion of volume renderings with lobes segmentation (top right); Veo sagittal (bottom left).

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Figure 8. Coronal image of the abdomen and pelvis comparing FBP (left) to Veo (right). Veo image demonstrates higher image quality and less noise compared to the FBP image at 0.97 mSv (obtained by ICRP Publication 102, using a one-year-old abdomen and pelvis factor of 0.03 x DLP).

Figure 9. Coronal image of the abdomen and pelvis with low density lesions in the liver comparing FBP (left) to Veo (right). Lesions are better demonstrated in the Veo image at 1.88 mSv (obtained by EuR-16262 EN, using an abdomen factor of 0.015 x DLP and a pelvis factor of 0.019 x DLP).

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over the last decade, clinicians have witnessed remarkable advancements in CT imaging. This includes the emergence of hybrid imaging, which brought CT together with functional imaging systems such as PET and SPECT, multi-slice CT, and techniques that significantly lower radiation dose.

GE Healthcare has been a leader introducing innovations that have redefined the clinical value of CT imaging. Now, the company is charging ahead with another evolution in CT technology that promises to help clinicians confidently view even hard-to-see lesions—high definition imaging that enhances spatial resolution.

CT has long been recognized as an imaging leader in spatial resolution, which is the ability to distinguish two separate structures that are a small distance from each other. Yet, many improvements in spatial resolution over the years were incremental—that is, until the introduction of the Discovery* CT750 HD system.

“The Discovery CT750 HD provides better spatial resolution and image quality than other systems in our facility,” says William P. Shuman, MD, Director of Radiology at the university of Washington Medical Center (uWMC).

Dr. Shuman’s colleague, Kelley R. Branch, MD, Assistant Professor in Cardiology at uWMC, agrees that “the Discovery CT750 HD in high definition mode offers high detail spatial resolution needed for cardiac imaging.”

Value in cardiac imaging

Increased spatial resolution was always desired for cardiac imaging, Dr. Branch says, especially when imaging smaller patients and arteries.

This same detailed resolution also benefits characterization of plaque. “Better spatial resolution helps us improve the delineation of plaque characteristics,” adds Dr. Branch.

“We can see the lumen and the outside wall of the coronary artery, and assess if the plaque is a concern that requires follow up.”

Dr. Shuman believes high spatial resolution in CT will play an important role in aiding them to detect disease within smaller vessels. Historically, he says, this has been a weakness of CT—the inability to successfully image the

smaller branch vessels. This led to patients undergoing further evaluations, such as a diagnostic cardiac catheterization, after a diagnostic CT study.

“There is a good proportion of cardiac disease located more distally after the first and second branches that may still cause symptoms,” Dr. Shuman explains. “It is critical to be able to assess the peripheral branches for coronary artery disease, as well as capturing the extent of disease in the proximal coronary artery.”

CT perfusion studies are another potential area for greater clinical utility resulting from higher spatial resolution. “With CT perfusion, it comes back to precision,” Dr. Branch explains,

“and the confidence that what you are seeing is really there.” When evaluating the myocardium with higher spatial resolution, for example, he is able to conduct more advanced calculations based on the imaging study—calculations that can help assess myocardial blood flow.

Impact on patient care

In describing the benefit of enhanced spatial resolution, Dr. Branch points to the high negative predictive value of CT. “As the spatial resolution increases, our confidence in the study improves significantly and we are more confident that we don’t have to conduct further tests to rule out the presence of disease.”

This capability is very important not only for triaging chest pain patients in the ED, but also reducing the overall cost of a patient’s episode of care. Having the ability to provide patients a rapid answer is beneficial; not just for their care, but also to determine which chest pain patients can be discharged from the ED.

“This consumes less resources and leads to lower costs and we are able to see atherosclerosis that we haven’t seen before,” says Dr. Branch.

While coronary artery disease may not be an immediate issue for these patients, it can develop in the future and Dr. Branch sees it as an opportunity to engage the patient to change their behavior. “It is our hope that patients will benefit by adopting a move toward a healthier lifestyle,” he says.

Reaching New Heights in CT Cardiac ImagingThe impact of spatial resolution at the university of Washington Medical Center VR heart


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The double whammy

Both Drs. Branch and Shuman credit another GE innovation on the Discovery CT750 HD with helping improve spatial resolution—ASiR* (Adaptive Statistical Iterative Reconstruction).

“using techniques such as ASiR, we have seen improvements in low contrast detectability (LCD),** but adding HD on top of that helps us use CT to examine the branch vessels and in some cases, provide us the images we need for a definitive evaluation of coronary artery disease after an inconclusive SPECT exam,” Dr. Shuman says.

Dr. Branch describes the benefit of ASiR with HD as getting a noticeable improvement in spatial resolution without an increase in dose, almost like

“getting more information for free.” HD provides an increase in spatial resolution and ASiR may enable LCD improvement without the need to increase dose.** That, he says, continues to advance clinical precision. “Now CT is presumed a lower dose study, particularly important for younger patients.” Dr. Branch also appreciates the lower noise and virtually artifact free images when using ASiR.

“If we are struggling with spatial resolution in patients whose exams are likely to have a high level of noise, such as obese patients, we can use ASiR and HD to obtain a diagnostic study,” says Dr. Branch.

He also finds that the fine spatial resolution obtained from the use of HD helps address the issue of artifact from blooming of calcium. Notes Dr. Shuman,

“We used to exclude patients with calcium; now we don’t.”

“These improvements—ASiR and HD—are impressive by themselves, but when used in combination we see a substantial difference across a very broad range of studies in spatial resolution and LCD,” Dr. Shuman continues. When faced with new developments such as HD, he advises his peers to not become consumed with the lack of peer-reviewed literature or research. “until users begin to integrate a technology into their standard-of-care, it will take time for new innovations such as HD. You just have to be willing to dive in and try it yourself.” And he bets that the user will encounter a series of pleasant surprises and find it unlike any other technique.

Looking to the future, Dr. Branch believes higher spatial resolution will be a step toward redefining the role of CT imaging. “With these advancements, one can foresee a future where cardiac CT could be the first line of assessing (cardiovascular) symptoms and assessing high risk patients, and potentially changing therapy based on cardiac anatomy.” n

Dr. William P. Shuman

William P. Shuman, MD, is Director of Radiology at uWMC and Vice Chairman and Professor for the Department of Radiology. Dr. Shuman received his medical degree from State university of New York Syracuse, and completed a residency in radiology at the university of Vermont. Dr. Shuman is one of the leaders in creating cardiac CT at uW. outside of uW, Dr. Shuman has served as Associate Editor for the two leading academic peer reviewed journals in Radiology, is currently on the Appropriateness Committee of the American College of Radiology, and is the President of the Society of Body CT/MR.

Dr. Kelley R. Branch

Kelley R. Branch, MD, is Assistant Professor in Cardiology at the university of Washington Medical Center. Dr. Branch received his medical degree from Jefferson Medical College, and completed a residency in internal medicine at the university of Michigan Medical Center. In 2003, Dr. Branch received the American College of Cardiology Merck Fellowship Award, and, in 2007-2008, the Cardiology Teaching Excellence Award and the School of Medicine CME Teaching Award from uWMC. He is also a founding member of the SCCT (Society of Cardiovascular Computed Tomography) and is actively engaged in several clinical studies.


Vessel tree

High resolution with ASiR


C L I N I C A L V A L u E o P T I M A C T 6 6 0

Bigger is not always better. In the world of CT imaging, it is efficiency and quality that matter. That’s why clinicians across Europe and the Middle East are embracing the optima* CT660§—a new CT system that is eco-friendly and delivers high-quality imaging.

At his private practice in Burbach, Germany, Hans-Martin Klein, MD, relies on the latest CT, MRI, and ultrasound systems to deliver high-quality imaging across all exam types. Located near the geographic center of Europe and a major transportation hub, Prof. Klein’s patient base extends well beyond German borders.

“our focus is on quality medical imaging that covers all pathologies,” he says. “We do not compromise on diagnostic power and select systems that are near the top of the clinical application trends.” In concert with his focus, Prof. Klein wanted a CT system that would deliver the high-quality images his referring clinicians and patients have come to expect.

Prof. Klein is a strong promoter that advanced imaging must also balance with patient dose considerations. In his review of CT systems for his practice, he searched for the right solution that would allow for meaningful and significant dose reduction in accordance with ALARA principles.

“The optima CT660 is the right balance for us,” he adds, with the right development focus. It includes advanced technology such as ASiR*, a dose reduction technique.**

Today, Prof. Klein’s private practice performs an average of 45 imaging studies each day. He can also reconstruct 3D batch files, which helps streamline his workflow. The system has lived up to its full potential to consistently and reliably handle the daily exam volume in his busy practice.

For Prof. Klein, the most important aspect of the optima CT660 is quality.

Eco, Patient, and Physician Friendly: Advanced Low-dose Imaging Without Compromise



“our focus is on quality medical imaging that covers all pathologies.”

– Prof. Hans-Martin Klein


C L I N I C A L V A L u Eo P T I M A C T 6 6 0

“our goal is the highest diagnostic imaging quality standard across all modalities,” he says. Thanks to the implementation of the system, he can now offer CT cardiac imaging studies to referring physicians and patients.

“The optima CT660 offers a large set of applications and excellent software for coronary evaluation,” Prof. Klein adds. “Both in cardiac prospective gated mode and in retrospective gating we obtain excellent images at low dose.”

It is the image quality at a low dose that impresses him most. “When one of our team members was told the dose on a neck-abdomen-pelvis exam, he thought the value only referred to one of the three sequences, not the total exam,” says Prof. Klein. They verified the dose was for the entire exam and the image quality was great, he adds.

Providing greater access to low-dose CT studies is a benefit for the radiologist and the patient. Prof. Klein is excited he can now offer additional low-dose capabilities to all patients, including pediatrics.

The system is both ecomagination and healthymagination validated, helping to save energy costs—up to 60% with the energy saving mode. The optima CT660 also has a smaller footprint than comparable systems, helping reduce or even eliminate the cost to expand an existing room or add an addition to the facility.

The optima CT660 is creating new high-quality imaging opportunities, such as advanced CT cardiac imaging, for many clinicians such as Prof. Klein. Packed with features and applications, it offers low-dose imaging while still delivering the diagnostic image quality he demands. What’s more, thanks to its compact design, it provides greater flexibility for installation and is kind to the earth by consuming less energy. Reliable and eco-friendly, yet powerful—the optima CT660 is helping redefine the next generation of affordable CT systems. n

Eco, Patient, and Physician Friendly: Advanced Low-dose Imaging Without Compromise

“The optima CT660 offers a large set of applications and excellent software for coronary evaluation.”

– Prof. Hans-Martin Klein

Hans-Martin Klein, MD, is a radiologist in private practice in Burbach, Germany. He completed his medical training at Aachen university Medical Center, where he later held positions in radiology, neuroradiology, and neurosurgery. Before starting his second private practice in 2011, he was Medical Director of Evangelist Jung Stilling Hospital an imaging center in Siegen, Germany, for six years. Prof. Klein owns or co-owns nine German patents for medical and radiation protection products, authored seven books and over 100 articles, and presented 37 abstracts at medical meetings.

About the facility

Prof. Klein’s private practice, Medical Center Siegerlandflughafen, provides multi-modality diagnostics of nearly all pathologies with advanced CT, MRI, and ultrasound systems. The center’s primary focus is to deliver quality medical imaging and it has a daily volume of 40 to 45 patients. Situated near the geographical center of Europe and a major communication hub, Prof. Klein’s patients extend well beyond Germany’s borders.

Prof. Hans-Martin Klein


C L I N I C A L V A L u E B R I G H T S P E E D E L I T E

Make Every Study Exceptional Delivering high image quality with lower dose

Toulouse, France, is renowned as a city on the cutting edge of European technology. As such, it is appropriate that Joseph Ducuing Hospital, located near the center of the city, is one of the first hospitals to install the BrightSpeed* Elite with ASiR*—a compact CT with advanced technology inside.

The hospital’s mission is to contribute to improving the health of the residents throughout the community. This is accomplished with a primary focus on quality across all care areas—the emergency room, surgery, maternity, endocrinology, a center dedicated to “rare illness,” and a center for tuberculosis assessments.

It is this focus on quality and patient outcomes that led Joseph Ducuing Hospital to select the BrightSpeed Elite CT system with ASiR. The hospital took great care in the decision to acquire this particular system, explains Cristian Livideanu, MD, a radiologist at the hospital. “Both referring physicians and patients are aware of the importance of dose in CT imaging,” he says. “The BrightSpeed Elite provides ASiR dose reduction technology and matches our requirement to fulfill the needs of the community.”

The hospital’s initiative to reduce dose used a variety of methods, including the low dose features on the BrightSpeed Elite system, such as ASiR, and newly optimized protocols. During the first three months of scanning, nearly 900 patients have benefitted by lower dose **. The hospital has seen a decrease on average of 35% for brain exams, 50% for thorax exams, 40% for abdominal exams, and 70% for extremity studies—all while maintaining the image quality they needed for diagnosis.

Dr. Livideanu says that the local medical community has embraced the new ASiR technology and they have been referring CT patients to the BrightSpeed Elite CT system. “Since installing the BrightSpeed Elite, we’ve seen a significant percentage increase in patient referrals,” Dr. Livideanu says.

BrightSpeed Elite is a 16-slice CT with advanced technology inside—providing a remarkable balance between system design and speed of acquisition, reconstruction, and post-processing capabilities to deliver the clinical information in a short time. Thanks to this technology, Dr. Livideanu can perform high-quality CT studies at a reduced dose and maximize patient throughput.

He considers the system a workhorse CT that can be used for virtually any exam—from routine studies to emergency cases. Dr. Livideanu is most impressed with ASiR for reducing dose and attributes exam volume growth to this feature.


Figure 1. Excellent spatial resolution obtained at high acquisition speed allows depiction of the aneurysm on left renal artery (35 cm coverage in 5 sec/1.75 Pitch/5.5 mSv [obtained by EuR-16262 EN, using a adult chest factor of 0.015]).


name of author


C L I N I C A L V A L u EB R I G H T S P E E D E L I T E

Dr. Cristian Livideanu

Cristian Livideanu, MD, is a radiologist at Joseph Ducuing Hospital in Toulouse, France, since 2008. In 2002, Dr Livideanu received his radiology degree in Romania where he also received the “Cum Laude” award at the Millénium Radiology Congress. His areas of interest include interventional radiology, vascular, ER radiology, and osteoarticular radiology.

About the facility

Joseph Ducuing Hospital, near the city center of Toulouse, France, is a nonprofit, public hospital that opened November 3, 1976. It actively participates in the social work of protecting and safeguarding the health of the population. The hospital’s quality objectives and ethics are based on principles and values that aim to provide the best possible healthcare. Services include radiology, emergency room, infant care, surgery, and tuberculosis assessments.

The new CT is also faster than the hospital’s previous 16-slice CT. “With a more robust acquisition, we can better manage the more difficult cases, such as apnea and pulmonary embolism,” Dr. Livideanu adds. “The new post-processing tools—Lung VCAR*, Thoracic VCAR, Autobone, and VesselIQ Xpress—help the radiologists streamline reading for faster report turn-around-times and provide accurate and clear assessment to the referring physicians, who also express their appreciation for the exceptional image quality.”

Even with the additional software tools and features, the BrightSpeed Elite with ASiR was intuitive for the technologist to learn how to operate and the radiologist to best utilize the workstation. Within one week, the staff learned how to adapt the new technology for use in all applicable clinical cases.

Improving CT dose management can help maintain CT as a useful diagnostic imaging tool for radiologists, referring physicians, and patients, Dr. Livideanu says. He is pleased with the decision to be one of the first to select a new BrightSpeed system in France.

“I would recommend the BrightSpeed Elite system with ASiR because of the system’s ability to enable dose reduction,” he explains. “This system should be present in all regions of France and elsewhere.”

Dr. Livideanu adds, “It is very amazing to see that we have conducted many CT exams with half the dose that we used on the same patient two years ago—and all without loss in diagnostic image quality.” n

Figure 2. Multi-phase abdominal acquisition (120 kVp, 70 to 150 mAs).

Figure 3. A low dose, 5 second acquisition on the sinus (120 kVp, 10 mAs, Pitch 1.375).

“The BrightSpeed Elite provides ASiR dose reduction technology and matches our requirement to fulfill the needs of the community.”

– Dr. Cristian Livideanu


C A S E S T u D Y A B D o M I N A L I M A G I N G

Joel F. Platt, MD, Professor of Radiology and Director of Abdomen Division, University of Michigan Hospital

High Quality, Reduced Dose Imaging in the Comprehensive Evaluation of Potential Kidney Donors

Acquisition protocols

Scanner Discovery CT750 HD

Scan type/slice thickness

Helical /0.625

Coverage 20 cm

Rotation time 8 sec

Total X-ray exposure time

2.6 sec for CTA series

mA Auto mA 260-380; NI 27.5

kVp 100

Recon kernel Standard

SFoV 50

DFoV 28

ASiR 30%

Contrast protocols

Type of contrast 370 mg/ml iodinated contrast

Contrast injection rate

4 ml/sec

Total contrast amount

100 ml

Saline injection rate

4 ml/sec

Total saline amount

50 ml

Abstract

MDCT has become our established method for comprehensive evaluation of subjects who are being considered as kidney donors. As these healthy subjects are often young, the goal of reducing CT dose is logical in this setting. However, the need for detailed vascular analysis requires high quality axial and 3D imaging. utilizing the Discovery* CT750 HD with the dose reduction technology, ASiR*, helps our facility achieve these goals.

Patient historyThe patient is a 31-year-old female healthy subject who is being considered for potential kidney donation.

Figure 1. Thin slice images demonstrate nice detail for resolution of arteries.

Figure 3. Note the normal parenchymal vascular anatomy for potential renal donors.

Figure 2. Shows kidney patency and absence of kidney masses.

Figure 4. Displays normal vessels and perihilar branching patterns for main renal arteries.


C A S E S T u D YA B D o M I N A L I M A G I N G

Joel F. Platt, MD, is Director of the Abdomen Division and Body CT and a Professor in the Department of Radiology at the university of Michigan (Ann Arbor). He is also on staff at the Veterans Administration Hospital at the university of Michigan. Dr. Platt received his medical degree from Boston university School of Medicine. He completed his residency training in diagnostic radiology at the William Beaumont Hospital (Royal oak, MI), where he also held the position of Chief Resident, and his fellowship training in Cross Sectional Imaging and Interventional Genitourinary Radiology at the university of Michigan Medical Center (Ann Arbor). Dr. Platt is certified by the American Board of Radiology and is a published author of numerous research papers, peer reviewed publications, book chapters, and scientific presentations. He is also a national and international lecturer on the topic of CT abdominal imaging.

About the facility

university Hospital is the university of Michigan Health System’s hospital for adult patients. The 11-story, 550-bed hospital first opened its doors in 1986. In its 1,796,262 square feet, the hospital houses diagnostic equipment, clinical laboratories, operating rooms, and inpatient and intensive care units.

Dr. Joel F. Platt

ResultsAxial and 3D image review revealed no renal masses, stones, or congenital abnormalities. Vascular analysis revealed a single right renal artery with an early perihilar branch and a single left renal artery. No venous abnormalities were detected. Dose for the entire CT examination was 5.25 mSv§ of the CT study requiring dose of only 2.47 mSv§.

ConclusionBased in large part on the CT exam results, the patient was selected as a suitable kidney donor with the left kidney deemed the best choice for donation due to findings for normal parenchymal and vascular anatomy. CT findings were confirmed at surgery. Imaging information was obtained with a significant reduction in radiation dose with high resolution imaging.

DiscussionImaging evaluation of potential kidney donors represents a challenge, as these are healthy, often younger, subjects in whom we would like to minimize radiation exposure yet obtain high-resolution images to confidently identify and display the pertinent vascular anatomy.

The Discovery CT750 HD can be utilized to help reduce radiation dose through dose modulation using 260 to 380 mA. In this case we further reduced dose by scanning at 100 kVp. In the past, these dose reduction technology resulted in poor image quality; however, applying a novel reconstruction technique, ASiR, allowed image quality to be maintained at a high level as required in this clinical setting.

As measured by mSv in this case, the radiation dose was more than 30% less compared to our typical examination prior to the Discovery CT750 HD and ASiR.**

The Discovery CT750 HD provides a new standard in image clarity and lower dose. The system enhances diagnostic imaging by providing new paths to clinical diagnosis and treatment decisions. By using the Discovery CT750 HD, ASiR enables potential renal donors to be scanned with low dose and provides a high-quality exam on a healthy, young patient. n

High Quality, Reduced Dose Imaging in the Comprehensive Evaluation of Potential Kidney Donors Figure 5. MIP of right kidney (left); MIP of left kidney, deemed best choice for kidney donor (right).

Figure 6. VR of right kidney (left); VR of left kidney, deemed best choice for kidney donor (right).

§ obtained by EuR-16262 EN, using an adult abdomen factor of 0.015*DLP



C A S E S T u D Y S P E C T R A L I M A G I N G

Shrinivas B Desai, MD, Director, Department of Imaging and Interventional Radiology1; Rozil J. Gandhi, DMRD, DNB, Registrar in the Department of Radiology1; and Joseph Sunith George, Clinical Applications Manager2

Characterization of Renal Stones using GSI

Patient historyA 39-year-old male presented with acute pain in left upper abdomen and flank with no history of fever or hematuria. ultrasound showed multiple calculi in the left kidney with mild hydronephrosis. Patient previously underwent surgery for right renal calculi. urine biochemistry did not show any pus cells. Patient was referred for non-contrast CT urogram.

Findings There were two calculi of average size, 1.3 cm, in the pelvis and middle calyx with mild hydronephrosis of the left kidney. Both the ureters and right kidney were normal. Hu values of the stones were in the range of 450 to 490. using a Gemstone Spectral Imaging dual energy CT scan, the calculated effective atomic number of the calculi was approximately 6.95 suggesting uric acid. The effective atomic number of uric acid is 7.0. The spectral Hu curve also showed a negative enhancement pattern.

These findings corroborated with the recurrent calculus disease in this patient. Further biochemical studies conducted on the patient showed high serum uric acid levels. Patient did not complain of joint pain.

Patient was diagnosed with gout, a disease of uric acid metabolism.

DiscussionToday in the practice of medicine, it is essential not only to treat the disease but also its etiology. A non-contrast urogram using a conventional CT scan would not demonstrate the constituents of the renal calculus. With the advent of dual energy scanners, we can now determine the constituents of calculi with the additional information, specifically calculation of effective atomic number, material density overlay and preparation of histogram and spectral Hu curve.

uric acid calculi occur in disorders affecting uric acid metabolism. Hence, apart from treating calculus, it is important to treat the basic metabolic disorder. Dual energy CT scans can also detect oxalic, mixed calcium, struvite, and cystine calculi. using GSI we now have the ability to distinguish mixed non-uric acid calculi and characterize their chemical composition.

By demonstrating the constituents of the calculus, GSI assists in guiding effective patient management. n

1Jaslok Hospital and Research Centre2GE Healthcare


Scanner Discovery* CT750 HD

FoV 50 cm

kVp 80 and 140


C A S E S T u D YS P E C T R A L I M A G I N G

Shrinivas B. Desai, MD, is Director, Department of Imaging and Interventional Radiology at Jaslok Hospital and Research Centre (Mumbai, India). He received his medical degree from Seth G.S. Medical College and K.E.M. Hospital and completed five post-doctoral fellowships in imaging, MRI, and interventional neuroradiology at the university of Manchester/Manchester Royal Infirmary & Crumpsall Hospital (uK), Lariboisiere Hospital (Paris), university of California San Francisco, and Massachusetts General Hospital (Boston). Dr. Desai has lectured internationally, held various editorial board positions in academic journals, including Editor-in-chief of the Indian Journal of Radiology and Imaging, and authored 43 articles and eight book chapters.

Joseph Sunith George, Clinical Applications Manager, GE Healthcare

Jaslok Hospital and Research Centre

Characterization of Renal Stones using GSI

Figure 1. Histogram with effective atomic number of Stone (left); Spectral Hu Curve shows negative enhancement (right). Both are typical of uric acid calculus.

Figure 2. Material density overlay showing uric acid in different color (above); volume rendering of kidney stones (below). Calcium and uric acid are shown in different colors.

Dr. Shrinivas B. Desai

Rozil J. Gandhi, DMRD, DNB, Registrar in the Department of Radiology

Dr. Rozil J. Gandhi

Joseph Sunith George


C A S E S T u D Y N E u R o I M A G I N G

Howard A. Rowley, MD, Chief of Neuroradiology, Professor of Radiology, Neurology and Neurosurgery, University of Wisconsin, Madison, WI, USA

CT Perfusion 4D in Stroke Assessment

Introduction

GE Healthcare CT Perfusion 4D software offers fast, easy-to-use, fully automated perfusion post-processing. A complete set of maps is generated including blood flow, blood volume, mean transit time, IRF T0, and Tmax. Tmax reflects the transit time to peak of the enhancement. It includes the delay of the arrival of contrast to any given location from its arrival at the artery RoI (IRF T0). Interactive tissue classification assists the user to determine the status of tissue based on blood volume, blood flow, mean transit time, or Tmax maps. Interactive volumetric functional maps allow for complete volumetric assessment to quickly localize areas of interest (Figures 3 and 4). Smart Map offers improved image quality and clarity, reducing spatio-temporal noise while preserving functional details with repeatable results.

VolumeShuttle* provides extended 80 mm coverage at up to 24% less dose with a single contrast injection compared to traditional 40 mm perfusion.

Patient history

A 57-year-old female fell at home, presents with left hemiparesis. tPA was administered at outside hospital.

Diagnosis

Right ICA clot (Figure 1B), Right MCA (M1) occlusion (Figure 1C) with acute right hemisphere infarction (Figure 2).

In this case, CT Perfusion assisted with assessing the response to the IV tPA administered at an outside hospital and as a triage tool for consideration of endovascular intervention. Despite the application of IV tPA, the patient still had severe ischemia on arrival. n

Figure 1. (A) Non Contrast (C) CTA right MCA(B) CTA right ICA

Scan types performed:

• unenhanced CT

• CT angiogram (CTA) of carotid arteries and circle of Willis (CoW)

• CT perfusion

Acquisition Protocol

Scanner LightSpeed* VCT

Scan protocol CT Perfusion using VolumeShuttle

Slice thickness 16 – 5mm images (8i x 2)

Coverage 80 mm

Rotation time 0.4 sec

Total elapsed time

52.0 sec

Total exposure time

15.2 sec

kVp 80

mA 500

Recon algorithm

Standard

SFoV Head (32)

Contrast Protocol

Type of contrast 370 mg/ml strength

Contrast injection rate

5 ml/sec

Total contrast amount

40 cc

Saline injection rate

5 ml/sec

Total saline amount

30 cc


C A S E S T u D YN E u R o I M A G I N G

CT Perfusion 4D in Stroke Assessment

Figure 2. CBV, CBF (top, left to right); MTT, IRT T0 (middle row); Tmax, Tissue Classification (BV-Tmax) (bot-tom row).

Figure 3. Sagittal Tmax, 5 mm slice thickness (top); coronal Tmax, 5 mm slice thickness (bottom).

Figure 4. Interactive Volumetric Map demonstrating right MCA (M1) occlusion with axial and coronal CBF.

(C) CTA right MCA


C A S E S T u D Y P E D I A T R I C I M A G I N G

Jonathan R. Dillman, MD, Assistant Professor, and Peter J. Strouse, MD, Professor of Radiology and Director, Section of Pediatric Radiology, University of Michigan Health System, C.S. Mott Children’s Hospital

Low-dose CT Imaging of CPAM for Surgical Planning


DLP 15.98 mGy

kVp 80

mA 49-53

Noise index 33.6

CTDIvol 1.19 mGy-cm

Pitch 1.375:1

Scan range I 87.5 top S 14.375, 0.625 increments, 2 mm thick (coronal and sagittal)

ASIR 30%

8 cc dose, hand injected

0.62 mSv (using chest ICRP conversion factor of 0.039)

Congenital pulmonary airway malformation (CPAM), which now includes both congenital cystic adenomatoid malformation (CCAM) and pulmonary sequestration, is a rare benign abnormality of lung development. They are commonly detected during routine prenatal ultrasound examinations. Serial fetal ultrasound or MRI examinations may be performed to assess for growth of the mass in utero during the last trimester of pregnancy. Prenatal imaging also allows for the assessment of CPAM-related complications, such as fetal hydrops (including heart failure) and mass-effect upon other internal organs.

While ultrasound is most commonly the imaging study of choice in utero, a variety of imaging studies can be performed soon after birth to provide further lesion characterization and assist in surgical planning, including ultrasound, CT, and MRI. Goals of imaging include assessing lesion location, extent, and whether or not the lesion has a systemic feeding artery. If a feeding artery is present, its origin and course should be established for surgical planning purposes. For example, if the CPAM feeding artery is located below the diaphragm, the pediatric surgeon may have to open the abdomen in addition to the chest.

At our facility, CT radiation dose has been minimized in various ways. one of our most effective means of putting the ALARA (As Low As Reasonably Achievable) principle into place has been our implementation of ASiR (Adaptive Statistical Iterative Reconstruction) in conjunction with our Discovery* CT750 HD scanner. ASiR,* an iterative approach to reconstruction, is capable of reducing image noise without degrading anatomical integrity. This may allow for dose reduction in children while maintaining diagnostic image quality.**

The following case highlights the importance of ASiR in pediatric imaging for a confident diagnosis at low dose levels.

Patient historyA one-day-old full term (39 weeks) newborn with left-sided chest mass was originally recognized during second trimester prenatal ultrasound. In utero, chest mass was determined most likely to be a CPAM.

Immediately following birth, infant had respiratory difficulty. A portable chest radiograph confirmed a mass within the left lower chest demonstrating significant mass effect on adjacent structures (Figure 1), confirming the fetal ultrasound findings. Patient also suffered a pneumothrax (collapsed lung), required intubation for mechanical ventilatory support, and was referred to CT angiography (CTA) for further characterization of the chest mass and to identify the location of any feeding vessel.

** In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task


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C A S E S T u D YP E D I A T R I C I M A G I N G

Impact of kVp and mAs on dose

As radiologists know, when kVp is reduced, mAs must be increased to reduce image noise and maintain image quality. However, such an increase in mAs does not impact patient radiation dose in the same manner as does a higher kVp. Adjustments in kVp affect dose in an exponential manner, while modifications to mAs are linear. For example, doubling the mAs doubles the dose, while an increase from 80 to 140 kVp causes a five-fold increase in the dose (assuming a fixed mAs).1 Therefore, substantial dose savings can be achieved by lowering kVp even if it requires increasing mAs.

Reducing kVp while slightly increasing mAs has additional potential benefits for pediatric patients beyond radiation dose reduction. A lower kVp level yields more contrast between the bright and dark areas on the image (increased contrast-to-noise ratio); such increased image contrast is desirable for certain CT studies, such as CT angiography and CT enterography. These low kVp concepts have much potential and require further study that is specific to the pediatric population.

Reference: 1 Huda W, Vance A. Patient Radiation Doses from Adult and Pediatric CT. AJR 2007; 188:540-546.

Low-dose CT Imaging of CPAM for Surgical Planning

Figure 2. Four axial contrast-enhanced 2.5 mm CT images of the chest using 30% ASiR show a large mass (arrows) filling the left hemithorax. The mass displaces the heart, descending thoracic aorta, and esophagus to the right. Small areas of focal water attenuation within the mass (within the circles) were due to secondary lymphectasia at pathology. An umbilical arterial catheter (blue*) is present within the aorta.

Figure 1. Initial portable anteroposterior (AP) chest radiograph demonstrates a large mass (arrows) within the left lower chest with mass-effect upon mediastinal structures, including the heart, esophagus, and descending thoracic aorta.

A

*

C

*

D

*

B

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C A S E S T u D Y P E D I A T R I C I M A G I N G

Jonathan R. Dillman, MD, is an Assistant Professor, Department of Radiology, Section of Pediatric Radiology, university of Michigan Health System and a pediatric radiologist at C.S. Mott Children’s Hospital. Dr. Dillman graduated Summa Cum Laude with a BS in Chemistry at Butler university (Indianapolis, IN) and received his medical degree from Indiana university School of Medicine (Indianapolis, IN). Among his numerous awards and recognitions is an RSNA Roengten Fellow Research Award (2009), Best Poster Award, the 34th Scientific Assembly of the Society of uroradiology (2009), Best Poster Award, the 38th Scientific Meeting of the Society of Gastrointestinal Radiologists (2009), John Caffey Award, Best Case Report, Society for Pediatric Radiology 53rd Annual Meeting (2010), and Mentor of the Year, Junior Staff, university of Michigan Health System, Department of Radiology (2010). Dr. Dillman currently serves on the editorial board of Pediatric Radiology (Genitourinary Radiology).

Dr. Jonathan R. Dillman

Peter Strouse, MD, is a Professor in the Department of Radiology and Chief of the Section of Pediatric Radiology at C.S. Mott Children’s Hospital. He earned his medical degree from the university of Michigan. Dr. Strouse completed two fellowships at the university of Michigan, one in pediatric radiology and the other in cross-sectional imaging. He is certified in radiology as well as pediatric radiology. Dr. Strouse’s clinical practice involves most facets of pediatric imaging. His research interests are pediatric abdominal imaging and pediatric musculoskeletal imaging, particularly applications of cross-sectional imaging (sonography, CT, and MR) in these areas.

Dr. Peter Strouse

FindingsPatient was diagnosed with a large CPAM/pulmonary sequestration involving the left hemithorax with systemic arterial supply arising from the descending thoracic aorta above the level of the diaphragm. The large mass caused rightward shift of mediastinal structures, including the heart, descending thoracic aorta, and esophagus. Coronal reformatted CTA images confirmed diagnosis of CPAM and clearly depicted a large feeding artery (Figure 3B).

Patient underwent surgical resection the following day. Patient discharged after two weeks and the infant was doing fine at his one-month post-surgery follow-up clinical appointment.

DiscussionWhile ultrasound and MRI can also be used to diagnose and characterize CPAM and sequestrations, both imaging techniques pose limitations. ultrasound may be limited in depicting the origin and exact course of a feeding vessel and is highly dependent upon both the operator and the sonographic window, which can be impacted by air in bowel loops in the upper abdomen and air in the lungs. MRI is commonly a 30 to 60 minute study that often requires sedation for pediatric patients. Medical management of critically ill children in the MRI environment can also be challenging.

CT has historically been the imaging study of choice for the evaluation of CPAM—high resolution imaging enables a confident diagnosis and, by depicting the feeding vessel, provides the information required for surgical planning. CT allows for very rapid imaging in an environment that is more conducive to managing critically ill children.

At C.S. Mott Children’s Hospital, concern regarding infant/pediatric radiation exposure from CT dose has been partly allayed with the recent implementation of ASiR. In situations such as this case where an infant’s medical condition is tenuous and unstable, the rapid imaging capabilities of CT coupled with the low dose achieved through ASiR enable us to make a very confident diagnosis while minimizing the radiation dose imparted.**

In our experience, we have consistently achieved dose levels of about 1 mSv or lower at 80 kVp with 30% ASIR in very young children, enabling us to image gently, minimize any possible radiation-related concerns, and provide the necessary information our pediatric surgeons require for surgical planning. n

** In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task

Figure 3. Coronal reformatted and axial maximum intensity projection (MIP) images excellently depict the presence of a large feeding artery (black arrows) to the mass (white arrows). Based on this finding, the diagnosis of congenital pulmonary airway malformation (CPAM)/pulmonary sequestration was confirmed. An umbilical arterial catheter (blue*) is present within the aorta.

A B

***

*


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In April 2010, GE Healthcare unveiled the optima* CT660§, a next generation, multi-slice CT system that is the first healthcare product to be ecomagination and healthymagination validated. Yet, the optima CT660 is more than a system designed to embrace these two initiatives. It inherits high performance and clinical utility from other GE leading CT systems, providing value in addition to placing strong considerations on patient and Earth friendliness.

System Design Combines High Performance with Patient, Earth FriendlinessBy Naoya Monden, Global CT Marketing Product Manager, GE Healthcare

ecomagination is based on resolving the far-reaching environmental problems the world faces...the “eco” represents both “ecology” and “economy.”

– Naoya Monden



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ecomagination

This initiative is based on resolving the far-reaching environmental problems the world faces. The “eco” in ecomagination represents both “ecology” and “economy.” Companies and individuals are becoming increasingly aware of environmental issues, and healthcare is no exception. In fact, many hospitals now require environmentally-friendly products.

The optima CT660 is the first CT system to be ecomagination validated. The system is based on the concept that we should contribute to the protection of the environment by meeting the needs of clients requiring high energy efficiency products. Specifically, the optima CT660 Energy Saving Mode can reduce Co2 emissions by more than 60%.

healthymagination

This initiative is based on the idea that more people should be able to receive more affordable and high-quality medical care, healthymagination is supported by three pillars: cost, access and quality.

Cost translates to affordability

Cost relates not only to the initial “price” of the system but also to improvements in operating efficiency. Similar to the energy saving mode of home electronics and appliances, the optima CT660 Energy Saving Mode can reduce electricity cost by reducing extra power with a timer-controlled oN/oFF switch. This mode allows energy savings up to 60% compared with conventional systems. In monetary terms, this translates to an annual savings of approximately ¥430,000 yen (approximately $5,200 uSD). To illustrate, the annual power consumption figures attained with and without the use of Energy Saving Mode are compared in Figure 1.

Reducing costs also means using less space. When an older, conventional CT system is replaced with a newer system that has a larger body or console, the siting cost is often higher. For instance, if a single- or dual-slice CT system is replaced with a 64-slice CT system, the CT room often needs to be remodeled. However, in 90% of these cases, replacing a current GE CT system with the optima CT660 in the same CT room avoids extending the room (see Figure 2).

Increasing the operating efficiency of a CT system requires reducing the waiting time for tube cooling—and this often requires a more expensive, higher capacity X-ray tube. Yet, the optima CT660 when equipped with ASiR—can substantially reduce the burden on the X-ray tube leading to an increase in operating efficiency. The use of ASiR may allow for scanning at lower mA and less anode heat, thereby reducing tube cooling limitations and potentially increasing the number of examinations per day.

Figure 1. Comparison of annual power consumption attained with and without use of Energy Saving Mode. “Active” is the use of Energy Saving Mode.

Figure 2. Sample room layouts for the optima CT660.


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Naoya Monden, Global CT Marketing Product Manager, GE Healthcare

Naoya Monden

An increase in both examination efficiency and operating efficiency requires patients to be rapidly examined during their stay in the examination room. While multi-slice CT systems have substantially reduced scan time, patient positioning time has not greatly improved. The optima CT660 is based on the concept that streamlining patient positioning is an integral component of the total solution. It displays the name of incoming patients on the monitor screen, helps the medical staff to set the patient smoothly and easily using the Default Patient Positioning Function, and confirm image quality after the scan via fast recon speed.

Access to more people

With a smaller footprint, the optima CT660 can be sited in more facilities constrained by a lack of space. Yet, these sites shouldn’t have to compromise on quality or abandon acquiring a premium CT system. The optima CT660 offers both—a high-performance CT with a space-saving design. In fact, facilities can reduce the installation area by up to 24% compared to conventional CT systems (ratio to our products), or in a room that is at least 15 square meters (Figure 2).

The gantry is also downsized to save space, which also helps enhance staff efficiency by opening up traffic lines. Patients also may feel less oppressed in a small gantry when lying down on the CT table.

Enhancing the quality of care

Since the introduction of the multi-slice CT system in 1998, these systems have progressed dramatically in the ability to generate thin-slices coupled with high speed and clinical performance. As a result, CT angiography and cardiac examinations have become widespread, if not routine in many healthcare institutions.

Today, CT exams offer high-quality, minimally invasive diagnostic techniques. However, there is a greater awareness today of patient exposure to dose resulting from a CT examination. Fortunately, GE Healthcare has been planning the development of products based on the idea that both dose and image quality are important factors in providing quality medical care. In 2008, GE led the industry by introducing a state-of-the-art image reconstruction technique known as ASiR (Adaptive Statistical Iterative Reconstruction) on the Discovery* CT750 HD. Today, ASiR is available on the optima CT660.

ASiR dose reduction technology may enable a reduction in pixel noise standard deviation. This algorithm may allow for reduced mA in the acquisition of diagnostic images, thereby reducing the dose required.**

As evident by the introduction of the optima CT660, CT design and development has reached a new turning point. It is possible for new generations of CT systems to provide clinically excellent performance and while simultaneously being “friendly” to patients, “considerate” to the Earth, and “healthy” to the hospital’s financial management. n

The optima CT660 is based on the concept that streamlining patient positioning is an integral component of the total solution.



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one Seamless Workflow EnvironmentBy Laurent Stefani, Global Marketing Manager, Dexus, and Paul Edwards, EMEA Product Manager, Dexus

“Dexus provides our facility with the ideal workflow environment, allowing easy collaboration between colleagues, while providing access to data from a workstation, PACS, or home.”

– Dr. Richard A. Kane

one solution that streamlines image postprocessing. You asked for it , now we’ve delivered it . GE Healthcare introduces Dexus,* a workflow environment that optimizes reading experience and productivity from image acquisition through results reporting. Built on the trusted GE AW and Centricity* platforms, Dexus links imaging devices, clinical applications, and IT for access to advanced visualization tools across modalities and patient care settings—whether the emergency room, clinical area, or physician office.

As integral components of the Dexus environment, AW Workstation and AW Server provide the portal to a broad portfolio of robust, easy-to-use clinical applications. By streamlining post-processing and synergizing imaging techniques, Dexus answers productivity needs across CT, MRI, PET, SPECT, and Interventional modalities. The AW Server converts virtually any PC, laptop, or PACS desktop to a 2D, 3D, and 4D post-processing workstation. This capability lets clinicians remotely review and share images in real time, enabling close collaboration with internal clinicians, stronger referring physician partnerships, more confident diagnoses, and better patient care.

“For groups like ours with radiology sub-specialists available for consult, it’s very useful that they can give their advice no matter where they are located,” says Fred Cohen, MD, Clinique Médipôle Saint-Roch (Cabestany, France). “They could be anywhere—they just use the software tools and provide feedback.”


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one Seamless Workflow EnvironmentBy Laurent Stefani, Global Marketing Manager, Dexus, and Paul Edwards, EMEA Product Manager, Dexus

Dexus environment leverages and maximizes technology investments by seamlessly integrating with existing IT infrastructure. For example, integration with an existing RIS/PACS enables one-click access to the rich clinical AW applications and the ability to leverage worklists, hanging protocols, and reporting systems from one PACS desktop. Integration to GE Centricity solutions provides instant access to online post-processing and comparison of current and prior exams, eliminating storage islands.

“using this new version of the AW Server is very transparent to workflow,” Dr. Cohen adds. “With one click I can go directly to the server and begin reading cases without entering additional passwords or other information.”

As part of the Dexus environment, the AW Workstation and AW Server include a common user interface, optimized protocols, review steps and tools for each clinical application to guide simple image review and analysis.

With automated case preparation, studies are ready for interpretation as soon as they are opened—the processing is completed in the background. This includes bone removal or coronary tree segmentation, tracking, and labeling.

“Dexus provides our facility with the ideal workflow environment, allowing easy collaboration between colleagues, while providing access to data from a workstation, PACS, or home,” says Richard A. Kane, MD, St. Francis Hospital (Evanston, IL).

“With one click I can go directly to the server and begin reading cases without entering additional passwords or other information.”

– Dr. Fred Cohen


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Clinical solutions

As part of the Dexus environment, multimodality applications combine with customized workflow for radiology, cardiology, vascular, oncology, and neurology— providing one solution for virtually any care area.

For vascular studies, the Dexus environment provides a premium 2D/3D clinical analysis tool that enables fast, routine review. It simplifies complex studies such as plaque analysis, stenosis quantification, aneurysm measurement, and bone segmentation. What’s more, analysis tools are available across the enterprise so surgeons can fully interact with 3D images to precisely visualize cardiovascular anatomy.

The Dexus environment also brings a breadth of new enhanced applications in cardiology (see CardIQ Xpress Reveal article on page 6), neurology (see CT perfusion article on page 50), and oncology. By bringing these new applications together within the Dexus environment, AW and Centricity solutions come together to facilitate follow-up by enabling instant access to priors and streamlining comparisons over time.

The oncology application, oncoQuant, introduces a new focus on cross-modality oncology. It builds upon the Dexus foundation and synergizes available information to help clinicians diagnose, plan and guide interventions, and follow-up treatment.

“We can better collaborate with oncologists for monitoring patient progress throughout the treatment cycle,” explains Professor Yves Gandon, MD, Chief Radiologist of Medical and Functional Imaging, Hôpital Pontchaillou, CHu Rennes (Rennes, France).

The software monitors tumor progression and response to treatment. With automated and interactive access to quantitative information, clinicians can visualize, track, and manage multiple lesions and patient exams over time.

“The solution can also have a more positive effect on the quality of measurements,” Professor Gandon says. He believes oncoQuant helps with measuring and reporting tumor response for the Response Evaluation Criteria in Solid Tumors (RECIST) published rules.

Streamlined reading, simpler research, and streamlined workflow help enable clinicians to deliver a more immediate diagnosis. Dexus brings the power of one solution to medical imaging workflow so clinicians can access the information they need—when and where they need it. n

Laurent Stefani

Laurent Stefani is the Global Marketing Manager, Dexus, at GE Healthcare

Paul Edwards

Paul Edwards is the EMEA Product Manager, Dexus, at GE Healthcare


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The Importance of Spatial Resolution for High-quality Cardiac CT ExamsBy Vincent Norlock, Global Product Manager, and Jiahua Fan, PhD, Senior Scientist

Figure 1a. Standard definition image of calcified plaque and stent

Figure 1b. Reduced calcium blooming with HD imaging

Spatial resolution is important to the diagnostic quality of a cardiac CT exam because it directly translates to accurate, clear images—giving the physician the data to help correctly establish the extent of coronary artery disease (CAD) in those who have it, while clearing those without it .

Accuracy of CTA

Clinical trials have demonstrated that CCTA is a highly-accurate means of excluding coronary artery stenosis and that Coronary CT angiography (CCTA) is more likely to aid in the detection of CAD and less likely to overestimate its extent than some other testing modalities.

Challenges to more accurate CCTA reading

Accurate estimation of CAD is challenged by the presence of coronary calcium, stents, moderate-to-severe stenosis, and the visualization of bypass grafts.

Calcium

A highly calcified coronary stenosis can cause a “blooming” effect in CT images. The blooming appears to expand the boundaries of the stenosis into the surrounding voxels, increasing the apparent size of the blockage. A 2009 study using earlier, standard definition CT at Karolinska university Hospital1 specifically called out the limitation on PPV caused by vessel calcification. The study found that the “poor”

image quality segments were the result of calcification and it was the main reason for poor image quality in the LAD.

Images comparing earlier generations of CT to the Discovery* CT750 HD demonstrate that high resolution scanning reduces the blooming effect from calcium and aids in clearer visualization of the vessel lumen (Figure 1). This helps to overcome the appearance of increased severity in lesions with highly calcified plaque.


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Intracoronary stents

The introduction of coronary stents provided a reliable means of combating the effects of CAD. However, the artifacts potentially induced in the CT image by the stent may enlarge the stent boundaries and thereby increase the apparent visual size of the stenosis.

A study at Cornell university2 compared an earlier generation CT system to the Discovery CT750 HD. This study reported that the Discovery CT750 HD not only delivered impressive lumen area visualization, but also lower image noise. Both of these factors are important for the physician to accurately assess the extent of in-stent restenosis.

Moderate-to-severe stenosis

The cited studies show that agreement with invasive angiography decreases with moderate-to-severe stenosis. Previously, overestimation of the appearance of the severity decreased the specificity, especially in smaller vessels.3

The Discovery CT750 HD has the ability to accurately image vessels as small as 1 mm and provide the clinical reader with reliable information when diagnosing stenosis in the distal vessels.

Bypass grafts

The position and variation of coronary bypass grafts can add to the challenges listed above. The Discovery CT750 HD delivers clear images for accurate assessment of coronary anatomy and bypass graft conditions in a single scan. The high resolution cardiac scan modes allow for sharp visualization of both grafts and coronaries.

Vincent Norlock

Jiahua Fan

Vincent Norlock is Global Product Manager at GE Healthcare

Jiahua Fan, PhD, is Senior Scientist at GE Healthcare



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Comparing CT models

In 2010, the uK’s National Health Service’s ImPACT group published a report, Market review: Advanced CT scanners for coronary angiography.4 The ImPACT group gave each CT manufacturer requests for specific spatial resolution measurements along with instructions on how they were to be acquired. Each company then provided the ImPACT group at the NHS with results obtained from their own in-house testing.

While not participating in this ImPACT report, GE made the same measurements on the Discovery CT750 HD systems. A comparison of these results is shown in Table 1A and Table 1B.

The data show Discovery CT750 HD has the ability to resolve 18.2 lp/cm in the z-direction, allowing fine cardiac details to be seen. This high resolution is driven by the properties of the GE Gemstone* detector and dynamic deflection of the X-ray beam. When used in combination with GE’s ASiR* noise reduction technology, the Discovery CT750 HD delivers high definition cardiac scanning at optimized dose and noise performance.

Spatial resolution is not merely helpful in cardiac CT; it provides critical diagnostic assessments. The data show the Discovery CT750 HD has the highest cardiac spatial resolution of commercially available CT scanners. The Discovery CT750 HD allows clinicians to visualize vessels as small as 1 mm and, in some cases with ASIR** less than 1 mSv, in one exam they can count on.

References1 Limitations of 64-detector-row computed tomography coronary angiography: calcium and motion but not short experience. Acta Radiol. 2009 Mar;50(2):174-80.

2 High-definition multidetector computed tomography for evaluation of coronary artery stents: comparison to standard-definition 64-detector row computed tomography. J Cardiovasc Comput Tomogr. 2009 Jul-Aug;3(4):246-51

3 Diagnostic Performance of 64-Multidetector Row Coronary Computed Tomographic Angiography for Evaluation of Coronary Artery Stenosis in Individuals Without Known Coronary Artery Disease: Results From the Prospective Multicenter ACCURACY Trial, Journal of the American College of Cardiology Volume 52, Issue 21, 18 November 2008, Pages 1724-1732

4 Market review; Advanced CT scanners for coronary angiography,CEP10043 March 2010. Available at http://www.impactscan.org/.

Comparison of specificity and sensitivity in cardiac imaging

Philips Brilliance™ iCT Siemens SOMATOM Definition Flash™ Toshiba Aquilion™ ONE

Scan plane (x-y) spatial resolution, manufacturers specification [lp/cm]

Reconstruction filter CA CB CC CD B30f B36f B46f FCoI FCo3 FCo5

50% MTF 3.1 3.4 4.4 4.8 3.6 4.2 4.8 3.2 41 4.8

10% MTF 5.3 6.3 7.0 8.5 5.9 7.3 7.8 5.6 8.1 9.2

2% MTF 6.5 8.0 8.5 10.5 7.3 9.0 9.4 7.2 11.1 11.6

Off-center resolution (125 mm): Ratio off-center/center

CA~0.95; CB&CC~0.9; CD~0.8

~0.9 Data not available

Longitudinal (z) spatial resolution, manufacturer’s specification [lp/cm]

50% MTF 5 6.5 4.1

10% MTF 8 12 8.1

2% MTF 12 15 11.1

GE Discovery CT750 HD

HDS HDD HDDP

5.8 6.8 6.2

8.9 9.8 12.5

10.3 11.2 14.8

0.92

6.8

13.7

18.2

Table 1A Table 1B

Source: Table 1A. Market review; Advanced CT scanners for coronary angiography, CEP10043 March 2010; Table 1B. GE Healthcare.


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How did GE make these measurements?

using the ImPACT assessment guidelines, GE Engineer Priti Madhav created a testing protocol for Discovery CT750 HD. Together with Alyssa Nowak, CT Product Development Specialist, the in-plane and longitudinal resolution of both axial and helical cardiac scans was evaluated.

In-plane (x-y) measurements were made with a GEPP phantom. Longitudinal (z) measurements in cardiac axial mode were made using a slope 4-wire phantom while a gold foil phantom was used for cardiac helical measurements.

These measurements not only characterize the spatial resolution of the CT hardware but also the image reconstruction kernels used. In our tests, we measured only those kernels normally used for cardiac scanning. n

Figure 2. GEPP Phantom (left), Gold Foil Phantom (center), Slope 4-wire Phantom (right)

Alyssa Nowak

Priti Madhav

Alyssa Nowak is CT Product Development Specialist at GE Healthcare

Priti Madhav is Lead Engineer, System Physics and Image Quality, at GE Healthcare


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By Jean-Baptiste Thibault, PhD, Principal Scientist, CT Systems – Advanced Algorithms

Advancements in CT have increased dramatically during the past 10 years, offering a more effective non-invasive technique for examining patients without having to resort to exploratory surgeries that were once routine clinical practice. The growing importance of CT as a diagnostic tool increases the need for solutions that improve diagnostic information yet lower radiation to patients.

However, these advancements in CT technology are no longer driven solely by hardware components. Software— including reconstruction and image processing—is an important element to diagnostic accuracy.

Realizing this, GE Healthcare has developed a powerful class of new reconstruction techniques designed to explicitly include the modeling of data statistics into the reconstruction. ASiR,*

introduced in 2008, first demonstrated the potential of advanced statistical algorithms. In 2011, Veo*§ builds upon the foundation laid by ASiR by now including accurate modeling of X-ray physics and system optics. This robust, full model-based iterative reconstruction was designed from the ground up to enable improved image quality and to enhance imaging performance even under very low mA scenarios. Veo may enable diagnostic images at lower dose levels.**

Limitations of prior reconstruction methods

Since the introduction of clinical CT systems in the late 1970s, the same analytical Filtered Back-Projection (FBP) algorithm has been used as the basis of commercial CT reconstruction until now. To make the mathematics manageable, many simplifications and assumptions were made, including the following: the measured signal contains

no error due to photon statistics or electronic noise; the X-ray tube focal spot is an infinitely small point; the detector is also formed of points located at the center of each cell; and the reconstructed voxel is a point with no shape or size. As a result of these geometric and noise assumptions, FBP is an imperfect process.

First and most important, FBP ignores that the projection data are corrupted by quantum and electronic noise during acquisition. Instead, it may propagate and sometimes amplify noise into patient images, creating streaks and artifacts, which may hide pathology and valuable diagnostic information. This can can make low-dose imaging with standard reconstruction techniques a significant challenge.

The remaining three assumptions of FBP all deal with the geometry of system optics. While necessary from a mathematics point of view, these assumptions lead to a trade-off in image quality simply due to the fact that they do not give an accurate description of the data acquisition process in the CT system.

Model-based iterative reconstruction

Anticipating the need for high-quality, low-dose imaging in modern scanners, GE’s quest to develop a reconstruction algorithm that is modeled after system statistics and “real” optics, or the true status of the CT system, began in 2001. This led to the introduction of ASiR by GE Healthcare, the first breakthrough commercial iterative reconstruction algorithm for CT. By focusing on quantum and electronic noise in projection space, ASiR was able to deliver significant dose reduction potential in a computationally efficient manner and greatly improve image results.

The Model-based Paradigm: A New Frontier in Image Reconstruction

§Veo is 510(k) pending at FDA. Not commercially available in the united States.


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Figure 1. Advanced model-based approach to CT reconstruction.

Raw data

System optics

Final image

Iterative algorithm

Data statistics

Desired image behavior

The GE difference•

•

With Veo, our goal was to add geometric accuracy and X-ray physics modeling to attain the highest level of image quality regardless of complexity and length of time to develop, test, and implement. We believed that improvements in modern computing would continue to progress to the point where the complex reconstruction process could be performed in clinically acceptable times.

An important requirement for the reconstruction algorithm was to model accurately the system optics and the X-ray physics of data acquisition for a more realistic representation of the data acquisition process. This is important because system response changes depending on the location of each image element in the field of view relative to the scanning trajectory. The reconstruction algorithm also had to be adaptive—that is, adapt and react to the different types and densities of tissue, for instance, bone and soft tissue—including the ability to optimally reduce noise and preserve details in different areas, such as edges (high frequency content) and homogeneous regions (low frequency content). Finally, the algorithm provides a measure of confidence in each acquired data point—the data statistics—based on the physics of data acquisition to allow for independent control of noise in the reconstruction process. The latter is a unique feature of the Veo algorithm.

As a result, Veo solves the fundamental problem of image reconstruction (to produce images that most accurately match projection data) by directly optimizing the

Jean-Baptiste Thibault

Jean-Baptiste Thibault, PhD, Principal Scientist, CT Systems – Advanced Algorithms, GE Healthcare


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Figure 2. FBP Reconstruction (top) and Veo Reconstruction (bottom) of a low-dose abdomen-pelvis: Veo shows a clear improvement in the identification of renal nodules and the reduction of shading artifacts originating from the metal hip implant.

constrained function in Figure 1 for optimal image quality. This is different from other proposed approaches that combine sinogram processing and image filtering as separate steps to reduce noise, sometimes with unstable or unpredictable results. Instead, the mathematical formulation for Veo ensures that the desired images are obtained at the end of the iterative process.

With Veo accounting for the modeling of data statistics, X-ray physics, and system optics, the reconstruction performance was the next hurdle. Thanks to partnerships among GE, IBM, and Intel that led to optimized hardware and software platforms, a ten-fold increase in reconstruction performance was achieved in 2007. When coupled with further advances in iterative optimization algorithms pioneered by GE Healthcare, true of model-based reconstruction of clinical patient exams became a reality when Veo was introduced on the Discovery* CT750 HD.

Relaxing the trade-off between spatial resolution and noise

Before ASiR and Veo, radiologists learned to read through noise to identify anatomy and pathology. With FBP, higher spatial resolution is accompanied by higher image noise. on the contrary, a statistical method like Veo operates to explicitly reduce or eliminate image noise with the goal of obtaining optimum image clarity. It challenges the common trade-off to improve resolution while simultaneously reducing noise significantly and improving contrast.

This is a significant advantage of Veo relative to conventional FBP reconstruction. With advanced noise and physics modeling, Veo can accurately estimate the contributions from photon noise to the projections after dense bone and metal attenuation and significantly reduce shading artifacts (Figure 2). It also provides high spatial and contrast resolution around different tissue types and densities (Figure 3).

Veo represents a new foundation for CT image clarity, where improved model accuracy results in better images, featuring previously unattainable levels of combined noise reduction, resolution gain, improved contrast, and artifact suppression. This powerful model-based iterative reconstruction extracts more information from the acquired signal and opens the way to a bright future for low-dose, high-quality images. n


Figure 3. Comparison of FBP (A, C) and Veo reconstruction (B, D) showing significantly reduced noise combined with improved detail for a stent in the carotid artery.

A B

DC


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Dose management must be a high priority not only for Coronary Computed Tomography Angiography (CCTA) exams but also for routine studies. As such, it is important that technologists know the available options on the CT scanner to utilize dose reduction techniques.

By Patricia Zoltowski, Clinical Educator, CT Global Marketing

Techniques to Lower CT Dose

In fact, due to recent events concerning patient overexposure to CT dose in 2010, the FDA launched The Initiative to Reduce unnecessary Radiation Exposure from Medical Imaging. Through this initiative, the

“FDA is advocating the universal adoption of two principles of radiation protection: appropriate justification for ordering each procedure, and careful optimization of the radiation dose used during each procedure. Each patient should get the right imaging exam, at the right time, with the right radiation dose.”1

To ensure the right radiation dose, there are several actions that radiological technologists can employ to offer dose-reduction strategies in the imaging suite. These include the following:

Dose reduction strategies

1. Proper patient positioning on a CT scanner table is the first step to assure use of dose saving options. Higher noise images can occur when patients are not well centered in the scan field of view (FoV). By positioning the body at isocenter, the need to increase mA to compensate for the noise is eliminated.

2. Utilization of BMI charts. Technologists can reduce dose without image degradation by observing the patient’s weight and size. This can be based on the patients’ body habitus, or Body Mass Index (BMI). Some radiologists are suggesting that if a patient’s BMI is less than 30, a lower kVp and mA can be used.

3. Reducing mA and kVp. With mA, the relationship is directly proportional, meaning if mA is reduced by half, the corresponding dose is reduced by half. If kVp is reduced, the relationship is non-linear (exponentially lower). For example, if you reduce kVp from 120 kVp to 100k Vp (16.5% reduction of kVp) the result is a dose reduction of almost 40%.

4. Limiting the Scan Length/coverage to the ROI. Limiting the coverage of the scan will also help reduce dose. More accurately selecting the coverage area limits the start and end location and, therefore, reduces dose.

5. 3D Dose Modulation (AEC). AEC is an option with the ability to optimize dose to achieve the user inputted image quality (IQ) desired. When set up properly this may provide a dose reduction compared to a fixed mA scan set up to deliver the same IQ at the highest attenuation locations. Before the scan, the technologist selects the desired Noise/IQ. The scanner then automatically tailors the exposure based on the scout and body habitus of the patient.


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Dose management techniques on GE scanners

In addition to the actions outlined above, GE provides several dose minimization strategies that are built directly into the scanners. Most of these techniques have been available on GE scanners for many years.

1. AutomA and SmartmA. GE Healthcare’s answer for 3D Dose Modulation (AEC) is AutomA* and SmartmA*. AutomA optimizes the mA for each axial, helical, and cine scan. The benefit is to maintain a constant photon exposure for consistent image quality while providing dose reduction to the patient. AutomA changes mA across the z axis while SmartmA changes the mA across the x/y axis within a slice.

2. ECG modulated mA. When using retrospective gating in the cardiac helical scan mode, radiation dose can be reduced with the use of ECG Modulation. ECG Modulation allows for the variation of mA across the cardiac cycle depending on the phase of the cardiac cycle where maximum mA is applied and minimum mA is modulated across the rest of the phases. The range of phases for peak mA is prescribed by the user. Depending on the phase range selected for maximum mA, the dose reduction for a cardiac helical scan can be reduced. This technique is not only used on cardiac scans but also on gated PE studies, gated aorta studies and Triple R/o exams to alleviate motion from the heart.

3. Prospective gating. Prospectively gated CCTA utilizing GE Healthcare’s SnapShot Pulse dramatically reduces radiation exposure up to 83% with heart rates below 65 bpm compared to a low pitched helical cardiac acquisition. This is due to the X-ray being on during the prescribed cardiac phases only, meaning that data is not collected continuously across the cardiac cycle. This is an alternative to helical acquisition using axial step-and-shoot mode to acquire images during a specified phase of the heart cycle. This technique captures images of the heart and arteries using a series of three to four exposures taken in a step-and-shoot fashion. The X-ray is turned on only during the prescribed cardiac phases and is turned off when the table moves to the next location.

Figure 3. Technologist user interface

Figure 2. Illustration to show when peak (maximum) mA is applied.

Figure 1. 3D Dose Modulation.

Figure 4. Prospective gating – The pink box displays the specific phase of the cardiac cycle when the X-ray is turned on.


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3. Bowtie Filters. Bowtie beam shaping filters attenuate off-axis rays to minimize dose and reduce X-ray scattering effects. GE offers different bowtie filters to more closely match the body part being imaged. up to three different bowtie filters can be selected to more closely match the body part being images (head, body, heart) and patient size (adult or pediatric). Bowtie filters maintain a more uniform X-ray field at the detector to minimize the surface dose and reduce X-ray scatter. The bowtie filter results in an overall improvement in CT number accuracy, image uniformity, low-contrast detectability and imaging dose.

4. Reconstruction. ASiR* (Adaptive Statistical Iterative Reconstruction) is a new reconstruction technique that may enable reduction in image noise (pixel standard deviation). By reducing image noise, ASIR in-turn may allow a technologist to reduce the dose required to produce diagnostic-quality images. ASiR may also enable improvement in low contrast detectability. In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location, and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task.

5. Cardiac noise reduction filter. Selecting the appropriate cardiac noise reduction filter may also enable the technologist to further reduce dose while preserving the same image quality. This option will not automatically reduce dose. The cardiac noise reducing and edge preserving filters are labeled C1, C2 or C3. once the user chooses the appropriate filter, the mA can then be reduced manually.

In addition to utilizing the tools and techniques addressed in this article, it is important for each facility to implement a QA program to review scanning protocols, enact the utilization of pediatric protocols and, most important, as the FDA states in its initiative, ensure the appropriateness of use in CT scanning. To further ensure the safety of patients, facilities should support the continuing education of their technologists, including initial and ongoing certification in CT. n

Figure 6. Cardiac filter selection on CT Scanner.

Reference:1 Available at http://www.fda.gov/Radiation-EmittingProducts/RadiationSafety/RadiationDoseReduction/ucm199904.htm

Figure 5. Bowtie beam shaping filter.

Patricia Zoltowski

Patricia zoltowski, BS, RT (R), is CT Clinical Educator at GE Healthcare


B E Y o N D T H E S C A ND o S E S T R A T E G Y

Working Together Towards the Sub-mSv CT ExamRadiation dose from CT. It’s a concern that many share—clinicians, manufacturers, patients, and government agencies. While recent events have highlighted the importance of reducing medical radiation dose in the general population and news media, it is an issue that GE Healthcare has addressed for over 30 years.

At GE Healthcare, patient safety is our primary concern.

Consider the sheer number of CT exams performed each year. According to the latest CT census data from IMV1, an estimated 68.7 million CT procedures were performed in 7,640 hospital and non-hospital sites in 2007. This represents a growth of approximately 8% since 2003. During this same time, multi-detector CT became the standard of care in many clinical care areas, causing some to raise concerns over the potential for inappropriate radiation from CT imaging.

There is a certain irony with the use of CT imaging. Medical radiation in imaging technologies has enabled major medical advancements in the accurate detection of disease, the delivery of treatment, and the evaluation of treatment efficacy. They allow physicians to more easily visualize and characterize disease without the need for invasive procedures.

In fact, a recent study by Columbia university Professor of Business Frank Lichtenberg and based on data from the National Cancer Institute and Thomson Medstat, found that medical imaging innovation accounted for 40% of the decline in cancer deaths in the uS over the last decade. And, CT imaging has been called one of the most significant advances in the history of healthcare.

Yet, along with these powerful contributions to the quality and advancement of healthcare delivery, the issue of medical radiation also requires that physicians, healthcare facilities, and manufacturers work together to develop and evolve effective processes and systems to promote its appropriate use.

Kenneth Denison

Kenneth Denison, PhD, is CT Dose Leader at GE Healthcare

By Kenneth Denison, PhD, CT Dose Leader

Medical radiation in imaging technologies has enabled major medical advancements in the accurate detection of disease, the delivery of treatment, and the evaluation of treatment efficacy.


B E Y o N D T H E S C A N D o S E S T R A T E G Y

At GE Healthcare, we believe that this responsibility goes beyond the development and evolution of dose-reduction technologies. We support a comprehensive approach that takes into account the environment in which such equipment is used and those who are responsible for its implementation. We believe that a collaborative, system-wide approach to creating a dose-conscious healthcare system will help promote positive change—without limiting the progress of healthcare and its stewards to serve their patients well.

Starting with research

Promoting the best use of CT imaging is an important first step in lowering medical radiation dose. We believe, as a manufacturer, it is not enough to just build a better machine and hope it is used properly—we also have an invested stake in promoting the optimal use of the technology we make to help support the best patient care.

To that end, GE Healthcare is spending millions of dollars to fund research to identify and help define the standards, practices, and metrics required for any healthcare provider to implement a safe, effective, and efficient CT imaging program. To conduct this research in an independent and unbiased manner, GE has provided a grant to a third party, non-profit research organization focused on improving patient safety. Through collaboration with multiple physician researchers across multiple care settings—from small, rural hospitals to the largest, most complex academic medical centers—the organization will collect and analyze procedural data, practices, protocols, processes, and financial and outcomes data for the full imaging cycle in order to develop a consensus on the “is state” and the “best achievable state” of CT care.

The objectives of this research are to:

• Provide a forum for endorsement;

• Document the current “is state” of CT imaging across multiple care settings;

• Define the “best achievable state” across multiple care settings;

• Identify opportunities to help close the gap between the “is” and “best achievable” states;

• Address the opportunities for high-performance improvement around the full loop from patient assessment for imaging ordering, image execution, and reporting in the new value-based purchasing environment.

Driving this research is the idea that high-performance imaging programs ensure that the right procedure is done in the right way at the right time with the right dose, and the correct interpretation is accurately and quickly communicated to the patient. The results of this project will be published in the literature so that all stakeholders can benefit from them.

GE Healthcare believes that high-performance imaging programs occur only when a system-wide approach is taken and only when the program correctly addresses three key dimensions:

Leadership—the policies, processes, metrics, performance systems, culture, and change management that are characteristics of high performers;

Practices—the use of the best practices including appropriateness criteria, triage, protocol development, and scanning procedures; and

Technologies—the use of the right CT devices, dose-lowering features, and dose reporting/tracking/monitoring software.

A key output of the program will be assets to help healthcare providers assess their current leadership, practices, and technologies and assess gaps in the four “A’s”: awareness, accountability, ability, and action. Are we aware of performance gaps, best practices, and the benefits and risks of current and new technologies? Are there leaders or clinicians accountable to close gaps and adopt best practices? Do our leaders, clinicians, and staff members have the ability and know-how to close the gaps and ensure patient safety? Are we consistently taking action to close our gaps?

Solutions to close the gap

At GE Healthcare, our intent is to help our customers build high performance imaging programs using this system-wide approach. our focus is not only on the CT scanning technology we build, but on additional products and services that will help our customers build better imaging programs.

Today, GE Healthcare is working on DoseWatch, a new IT application that is expected to be commercially available this year. The goal is to allow clinicians to track, report, and monitor dose from multiple manufacturers and multiple imaging devices, including CT, interventional, mammography, and R&F. our customers will have one source of radiation dose information that can be used to optimize their performance, monitor sensitive patients, and help prevent errors.


B E Y o N D T H E S C A ND o S E S T R A T E G Y

Also look for Dose Check coming to GE Healthcare CT scanners this year. In response to an FDA request that stemmed from the Agency’s investigation into recent incidents of overexposure, the Medical Imaging and Technology Alliance (MITA)—a trade group comprised of the five major manufacturers of CT systems— developed Dose Check, an industry standard to provide healthcare providers with tools to set limits on the amount of radiation that will be delivered during CT scans (see sidebar).

The objective of Dose Check is to ensure there are notifications and alerts provided to the operator before a CT scan is prescribed above pre-determined radiation exposure levels.

How low can dose go?

In addition to adopting the new Dose Check standard, GE will continue its 30-year commitment to developing technologies that can lower dose without impacting image quality. over 900 installed GE CT scanners today are equipped with ASiR*, a proven technique for lowering dose while maintaining image quality. ASiR has been used in over 7 million exams to date.

our next generation dose reduction technique, Veo§ shows great promise in providing exceptional image quality at even lower doses. Available today in markets outside the uS, Veo is helping clinical users move toward our shared goal of routine, sub-mSv CT exams. Early adopters are seeing great results with Veo (see page 34) and we look forward to continuing to share their clinical cases with you in future issues of CT Clarity.

And there is still more to come. At GE Healthcare we recently completed our annual strategic planning process. Featured prominently in this year’s plan are still more dose-lowering features for our CT devices and new services to help build a high performance CT imaging program. We look forward to telling you more about these exciting developments in future CT Clarity articles.

Lowering dose isn’t just about building a better device. It’s about working together, to ensure that every patient receives the right exam, at the right time, and at the right dose. n

Dose Check

Dose Check is a NEMA XR-25 standard defined in conjunction with MITA and other stakeholders that notifies and alerts the operating personnel, generally technologists, when the estimated dose index is above the value defined and set by the operating group, practice, or institution. It is part of a department’s Quality Assurance process providing tools for auditing and tracking scans where Alert or Notification values have been exceeded.

Notification Value (NV) is the dose index that is above the institution’s established range for the protocol. NV is intended to be set at a level that would be considered above “routine” or “normally expected” dose, but not at such a high level as to pose a significant risk to the patient. Depending on the patient size or imaging need it may be appropriate to scan at a value above the notification value in order to achieve the diagnostic intent of the exam. Scanning is possible with no further authorization if the NV level is exceeded. GE encourages sites to establish appropriate notification values for all scanning. The AAPM has published a list of reference NV’s on its website at www.aapm.org.

Alert Value (AV) is a value established by the institution which will trigger an alert when the prescribed imaging series would cause the dose accumulated over the course of the exam to exceed this value. It is checked at exam level according to system presets and requires a user with authorization to confirm a scan exceeding this value. Manufacturers have pre-populated the AV at 1,000 mGy in accordance with FDA suggestion.

* In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task.

§Veo is 510(k) pending at FDA. Not commercially available in the united States.

Reference:1IMV 2007 CT Market Summary Report, IMV Medical Information Division, Des Plaines, IL. Available at www.imvinfo.com.


B E Y o N D T H E S C A N E D u C A T I o N

CT Clinical Education in the uS, Europe, Middle East, and Africa

For more information and to register for a CT Masters Course please visit www.gehealthcare.com/gectmasters or contact the CT Training Coordinator at 262-312-7148.

What’s New!Introducing the New Gemstone Spectral Imaging Workshop with James P. Earls, MD

This workshop is designed to provide radiologists and technologists with an in-depth understanding of how Gemstone Spectral Imaging (GSI) can be used routinely to aid in the diagnosis of patients and to assist clinicians with evaluating incidental or indicated findings.

The following topics will be covered:• Physics and theory of dual energy; • Benefits of monochromatic and spectral images; • Clinical applications of GSI; • Scanning procedures – protocols, presets, parameter choices,

reconstruction options; • Artifact reduction tools; and • Hands-on practice of the GSI Viewer on the Advantage Workstation.

SPECiAL iNTRODuCTORy

OFFER: 50% Tuition Discount

when paying with a credit card or 2 for 1 if paying with

a GE order Number.

uS Education

The CT Masters Series education consists of intensive and comprehensive courses developed and taught by expert radiologists, cardiologists, and technologists in multi-slice CT and advanced CT applications.

Current offerings:• Cardiac CT for Physicians* • Dose Reduction & Scanning Techniques• Cardiac CT for Technologists* • Gemstone Spectral Imaging• Peripheral CT Angiography • Advanced Neuroimaging Techniques• CT Colonography

*Endorsed by


B E Y o N D T H E S C A NE D u C A T I o N

Find the latest information on training for Europe, Middle East, and Africa at: http://www.gehealthcare.com/ clinicaleducation

Integrating dose reduction across clinical education curriculum

GE Healthcare’s CT Clinical Education team is integrating dose reduction techniques across its range of different customer training offerings.

This starts with the initial on-site applications visit through various customer support revisits. During these sessions, the CT clinical education specialist will work with the customer to optimize their protocols using the latest dose reduction technology where appropriate to deliver high image quality at the lowest possible dose.

Dose optimization courses

Participants will learn about CT radiation dose, including measuring dose delivered to the patient and CT dose optimization methods across the spectrum of patient examinations. The focus is to help users understand how changing scan parameters can affect both image quality and dose delivery applying ALARA principles.

Low dose cardiac training

Participants will learn all the aspects of cardiac CT from image acquisition to post processing techniques on the Advantage Workstation. The course will focus on helping users get the most from the technology while simultaneously reducing patient dose. The agenda includes a visit to a CT Department view Cardiac examinations being performed in a hospital setting. Courses are SCCT accredited and delivered in Plymouth uK.

AppsLinq™ – Remote training and support

Picture a clinical education specialist by your side whenever you need it. AppsLinq is a remote service application for troubleshooting and training that will help your CT department solve application-related problems, improve efficiency, and develop critical new skills. n

EMEA Education

“I am grateful for the opportunity to have attended the GE Masters Series GSI course taught by Dr Earls. During the 3-day course I learned the principles behind spectral imaging, and the current applications that have been developed or are in development. The hands-on instruction, both in scan acquisition and workstation image analysis was well done and very helpful. I enjoyed the open interactive style of education with ample opportunity to ask questions and practice skills. I would recommend this course to anyone interested in adding dual energy CT scanning to their service repertoire”.

– Larry Reif, MD, United Hospital System, Kenosha, WI

GE HealthcareComputed Tomography

© 2011 General Electric Company *Trademark of General Electric Company. CT-0470-05.11-EN-US

No company has done more to bring low dose to patients than GE Healthcare. That’s no coincidence — in fact, it speaks to the single purpose that guides our business: helping you deliver high-performance care.

Our approach is built upon a foundation of low-dose technology. But it also encompasses the best practices and industry exposure we’ve amassed for decades. The result is a true end-to-end partnership designed to help you provide lower dose patient care, more efficiently, and more effectively.

You’re here to deliver high-performance care. We’re here to help you do it.

www.gehealthcare.com/LowDoseCT

GREAT CARE BY DESIGN.

PartnershipDecades of CT experience have made us a strong, dedicated partner who understands healthcare’s complexities

ASiR*

Lower image noise while improving low contrast

detectability and image quality.

Gemstone* Spectral ImagingExpand information for clinical

diagnosis and workflow.

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