Applied Radiology

Technological advances designed to improve the quality and efficiency of radiology were again the highlight of the Annual Scientific Assembly and Meeting of the Radiological Society of North America (RSNA). Held November 26 through December 1, 2000 in Chicago, IL, RSNA 2000 hosted over 60,000 attendees from more than 100 countries. Among the myriad of new technologies and techniques, two particular areas stood out: digital imaging, notably digital mammography, and picture archiving and communications systems (PACS).

Challenges facing radiologists

In his President's Address, C. Douglas Maynard, MD, outlined the five major challenges facing radiologists today: workforce preparedness, expansion of knowledge, growth of the research enterprise, information management, and the globalization of radiology. "What we will become," he said "will depend largely on our collective response to these challenges."

Focusing on workforce issues, Dr. Maynard noted that the annual number of imaging procedures performed in the United States is expected to increase by 50% over the next 10 years--from 300 million to 450 million. However, the number of radiologists is only expected to increase by 20% during the same period. To avoid this potential manpower crisis, he said, outside agencies must stop placing caps on the number of new radiologists entering the field. "The marketplace, not arbitrary quotas, should determine the number of radiologists trained," he suggested.

Dr. Maynard also remarked that work in radiology could be done more efficiently with greater use of digital technologies and PACS. Although he acknowledged that such technological advances "will not gain widespread use in many places for a number of years," it is clear from the scientific presentations and the technical exhibits that this change is clearly on the way.

Mammography studies

Digital mammography--Approximately 32 million mammograms are performed annually in the United States, yet mammography has been the last modality to begin to move to a digital format. Several presentations at RSNA 2000 explored the role of digital technology in mammography.

One study, presented by John Lewin, MD, Assistant Professor of Radiology and Director of Breast Imaging Research, at the University of Colorado Health Sciences Center in Denver, CO, compared the diagnostic capabilities of full-field digital mammography (FFDM) and screen-film mammography (SFM) for cancer screening. The study, conducted at the University of Colorado and at the University of Massachusetts, included 6,768 women who underwent both FFDM and SFM.

A total of 183 women were found to have a suspicious abnormality leading to a biopsy. Of those, 51 were confirmed to be cancer. Of those with confirmed cancer, 18 were detected on both FFDM and SFM; 9 were detected on FFDM but missed on SFM; 16 were noted on SFM but missed on FFDM; and 8 were missed by both methods and were diagnosed when a mass became palpable within the year. These differences in detection were not statistically significant. FFDM, however, did show a statistically significant lower callback rate than SFM (12% versus 15%, respectively) and a lower rate of negative biopsies.

"While digital has not yet proven to be better than film mammography in detecting cancers," concluded Dr. Lewin, "it is an early technology that is likely to improve rapidly."

CAD technology--A second new technology for breast cancer screening, computer-aided detection (CAD), was the focus of a presentation by Timothy W. Freer, MD, Director of the Women's Diagnostic & Breast Health Center in Plano, TX.

In this study, the mammograms of 12,860 women screened for breast cancer underwent CAD interpretation. The films were initially screened by one of two experienced breast radiologists without knowledge of the CAD analysis. The films were then immediately re-evaluated with emphasis on the CAD-prompted areas.

A total of 49 new cancers were detected: 32 were found by both interpretations, 9 by the radiologist alone, and 8 only with the CAD review. All additional 8 cancers detected by CAD alone were in the very early stages. "CAD simply enhances our ability to detect these abnormalities at the earliest possible time," noted Dr. Freer.

One potential drawback was a 20% increase in both the recall rate and the biopsy rate. Dr. Freer pointed out, however, that this 20% corresponds directly with a 20% increase in detected cancers. "Current CAD systems are more accurate in the detection of suspicious calcium deposits than breast masses," said Dr. Freer. "But as the technology evolves, it should continue to improve our detection of masses as well."

The researchers concluded that, although these numbers appear encouraging, there is still a need for a large multicenter trial to verify these results.

Internet transmission of digital images

Digital images can be safely, securely, and inexpensively transmitted via the Internet, according to the results of a study presented by Michael P. Recht, MD, Musculoskeletal Radiologist and Head of the Section of E-Radiology at the Cleveland Clinic Foundation in Cleveland, Ohio.

The researchers randomly selected 9 magnetic resonance (MR) and 6 computed tomography (CT) studies from their clinical practice. The number of images per study ranged from 26 to 256. The studies were then sent between PCs running a commercially available viewer using one of the following methods: 10 BASE T, dedicated point to point T1 line, frame relay system with a port speed of 128, an ISDN line supplied by the local phone company, and via the Internet with both PCs connected to an Internet service provider by a T1 line.

Although the transmission speed over the Internet varied based on the time of day and day of the week, the overall speed compared favorably with the speed of transmission over the frame relay and ISDN lines. The quality of the images was judged to be the same, with no loss of information, for all modes of transportation.

"The implications are dramatic," said Dr. Recht. "Now a hospital or clinic can have a virtual radiology department. If there is no neuroradiologist available at your hospital to read your brain images, they can be sent over the Internet to a top neuroradiologist 1,000 miles away."

"The main concern has been the cost of sending images electronically," said Dr. Recht, noting that the cost for a high-speed telecommunication system can be prohibitive, especially for many smaller and remote hospitals and clinics, which often are even more likely to benefit from sending images digitally for second opinions. "Conversely," he said, "Internet service provider fees typically are fixed, and much more affordable."

"Although further work needs to be performed to demonstrate the utility of the Internet for transmitting images for a clinical practice," concluded the researchers, "it appears to be a promising method for transmitting images for use in multi-institutional research studies."

Technical exhibits

In addition to the more than 2,000 research presentations and posters, 275 refresher courses and "How To" workshops, and 980 education exhibits, RSNA was also host to more than 650 technical exhibits occupying more than 450,000 square feet of the McCormick Place Convention Center.

Mammography technology-- Demonstrations of enhanced breast cancer screening tools were prevalent among the technical exhibits. Among them were several digital mammography systems, CAD systems, and other innovations designed to detect more cancers at the earliest stage possible.

The FDA recently granted its first-ever approval for mammography screening directly from a computer workstation rather than traditional
x-ray films. This "soft-copy" reading system is now available on the GE Senographe 2000D from GE Medical Systems (Waukesha, WI).

The Senographe 2000D displays high-quality images 10 seconds after exposure, permitting quick verification of correct patient positioning. It is hoped that use of FFDM will decrease callbacks and offer better visibility of the entire breast area.

iMammogram.com (Westlake Village, CA) is marketing CAD services directly to the consumer via the Internet. iMammogram.com uses the ImageChecker from R2 Technology to provide what it calls CloserLook.

To request a CloserLook analysis, the patient logs on to iMammogram.com's website and requests and pays $75 for the service. iMammogram then retrieves the film from the original imaging center, scans and digitally analyzes the film to create a low-resolution paper printout with the markings superimposed on the image. The paper image and the unchanged original mammogram are returned to the imaging facility and the radiologist can then re-examine the original film. A digitized version of the mammogram is stored on a secure server at iMammogram.com.

Computerized Thermal Imaging, Inc. (Layton, UT) is using thermal imaging in an effort to enhance breast cancer detection. At this year's meeting, they demonstrated their Breast Cancer System 2000. This system provides a physiological, as opposed to anatomical, view of the breast by mapping minute temperature differences in the breast and analyzing them with sophisticated software.

This system, which uses no radiation, is painless and non-invasive. The patient lies face down on a custom table while a heat-sensitive camera takes a thermal picture. Abnormal breast tissue and cancerous tumors may produce a temperature pattern different from healthy breast tissue and benign tumors. It is not designed to replace the need for biopsies, only to serve as an additional screening tool to help the physician decide when and if a biopsy is necessary. It is currently undergoing FDA review.

Sectra (Shelton, CT) is addressing the concern of repeated radiation exposure due to the high number of mammograms the average woman undergoes. They displayed, as a work-in-progress, their new low-dose radiation mammography system, Sectra MicroDose Mammography. The system, expected to begin clinical testing in the second quarter of 2001, provides images comparable to that of current film-based mammography systems, but at one-fifth the radiation dose. The system is based on technology that permits detection and signal processing of each individual x-ray photon directly on silicon, permitting improved collection efficiency and signal-to-noise ratio.

Additional works-in-progress highlighted at RSNA 2000 in the area of mammography included a selenium-based mammography digital detector from the Lorad Division of Hologic (Bedford, MA) that incorporates Hologic DirectRay technology and the Lorad Digital Breast Imager featuring cesium iodide CCD technology.

Digital image management--Fujifilm Medical Systems USA, Inc. (Stamford, CT) featured Synapse V2 at this year's meeting. This latest version of the Fuji PACS system has been designed to permit additional integration of PACS and hospital-wide information systems. "Synapse takes the high-resolution content from the radiology department to the full hospital," said Peter McClennen, Fuji's National Marketing Manager for imaging and information networks.

A new feature of this system, Enterprise Multi-View, uses Web technology to integrate various physical locations with secure logins to permit users to access information from different facilities. This allows a network of facilities to communicate and share information even with different HIS/RIS systems, radiology reading groups, or separate databases. Synapse Access Over Networks (AON) is a suite of tools designed to permit on demand access of information over the slowest of networks. One tool, AON Subscription, permits remote physicians to "subscribe" to a set of information though a secure Intranet or Internet connection. Users can then access clinical information including diagnostic quality images from any remote location using MS Internet Explorer.

Toshiba America Medical Systems (Tustin, CA) demonstrated its simPACS product. As a DICOM and HL-7 compliant system, simPACS can be integrated with most imaging equipment. It features a Windows NT-based platform for both the review station and archives. Additionally, using standard phone lines and existing Internet technology, simPACS allows images to be electronically distributed with the Web server product.

Everyone was talking about. . .

Men and Women Listen Differently

Men listen with only one side of their brains, while women use both, according to a study presented by Joseph T. Lurito, MD, PhD, Assistant Professor of Radiology at Indiana University School of Medicine, Indianapolis, IN.

In the study, 20 men and 20 women underwent functional magnetic resonance imaging (fMRI) while listening to portions of the John Grisham novel The Partner . Most of the men showed exclusive activity on the left side of the brain, in the temporal lobe, which is classically associated with listening and speech. The majority of women showed activity in the temporal lobe on both sides of the brain, although predominantly on the left. The right side of the brain traditionally is associated with performing music and understanding spatial relationships, rather than listening.

"Our research suggests language processing is different between men and women, but it doesn't necessarily mean performance is going to be different," said Dr. Lurito. "We don't know if the difference is because of the way we're raised, or if it's hard-wired in the brain."

The finding may help with research regarding how men and women recover from stroke and brain tumors, said Dr. Lurito. It may also help guide brain surgeons in avoiding certain areas of the brain, depending on whether they're operating on men or women, he said.

"The key to simPACS is that the system is scalable and expandable," said Frederick Wagner, Toshiba's PACS product manager. "A facility can start with a modality-specific mini-PACS and grow into a multidepartment, multifacility system one step at a time."

Eastman Kodak Company (Rochester, NY) exhibited its DryView 8200 Laser Imager, expected to be available in early 2001. Providing 325 dots per inch (DPI) resolution, this dual-drawer imager is designed for general radiology and mid-volume computed radiography (CR) and digital radiography (DR) applications.

The DryView 8200 is configured with Kodak PACS Links with fully integrated DICOM printing and support for routing images to multiple network locations. PACS Link is also capable of converting image data from non-DICOM modalities into DICOM image data.

"With a PACS Link configured imager, customers gain a built-in architecture that provides a gateway to PACS and soft-copy viewing," said John Farrell, General Manager of laser imaging systems for Kodak's Health Imaging Division.

Digital archives--A major concern with digital images is the need for safe, reliable storage of data so they are readily available when needed. Several companies highlighted their capabilities for off-site storage of large quantities of digital images.

Agfa Corporation (Greenville, SC) announced new off-site storage options for its IMPAX R4 customers. The off-site storage archive is designed to complement the system's configuration, which includes primary on-site archiving. Pricing will be based on the number and type of exams stored.

Comdisco (Rosemont, IL) also unveiled its Storage and Access Management Services, a new suite of information management services designed to provide storage, access, and distribution of digital images. As part of this new service, Comdisco will plan, build, and manage hosted storage environments for customers' digital images. One of their services, High Availability Access Solutions, provides both primary and secondary storage using an Enterprise Access Device installed at the end user's facility. Digital information is entered into this device, then encrypted and transmitted via a secure network to two remote Technology Service Centers for storage.

"As hospitals continue to migrate to digital technology, they're becoming increasingly burdened by storage demands--both from a cost and resource perspective," said Mike Kennedy, General Manager for Comdisco Healthcare Group. "Comdisco's solutions allow healthcare providers to get out from under this. We provide the storage technology, we keep it current; customers simply request more storage when they need it, and we can manage the entire process for them off-site."

InSiteOne announced at RSNA 2000 that they have completed integration of web streaming technology into their InDex (Internet DICOM Express) digital imaging storage and retrieval service.

"Integrating web streaming enables images archived though our InDex remote archive ASP model to be viewed rapidly over any network or standard dial-up connections," said Richard Friswell, CEO of InSiteOne. This system allows physicians to remotely collaborate over diagnostic-quality images in real time and its open architecture integrates with any DICOM-compliant PACS or modality as well as hospital networks and information systems.

Additional technologies--Medison (Cypress, CA) announced that it has received FDA approval for VOLUSON 730, a Real-Time 4D ultrasound system. This system, which acquires images in up to 16 volume frames per second, provides real-time movement of the fetus and fetal heart. Employing a proprietary algorithm, it can also be used to trace the contour of anatomical structures such as the prostate, cysts, and lesions, and calculates the volume of the structure or mass. An integrated digital image management workstation digitally stores image data, patient files, and reports.

Philips Medical Systems (Best, The Netherlands) introduced the Integris Allura system, a dedicated interventional x-ray system designed to maximize 3D reconstruction. This system can be configured for vascular, cardiovascular, neurovascular, and nonvascular interventional and diagnostic procedures. It can also be combined with other modalities, such as ultrasound and CT, to support specific interventions. The Integris Allura also complies with DICOM standards and can be integrated into any compatible hospital image and information network. With the proper interfaces, images and data can be shared with PACS and RIS/CIS systems as well.

Hitachi Medical Systems America, Inc. also announced FDA clearance to market its new high-field performance open MR imaging system, Altaire. The system's capabilities include single-shot EPI, diffusion-weighted EPI, RF fat saturation, MRA with very short TEs and FSE with short inter-echo times, provided in an open gantry setting. In addition, the system is self-shielded. "Altaire's passively shielded design contains the 5 Gauss magnetic fringe field within an 18 by 22 foot scan room," said Sheldon Schaffer, Vice President and General Manager of Magnetic Resonance. "Since the room itself does not have to be magnetically shielded, sites can use windows and skylights to accentuate the open environment."

Conclusion

As Dr. Maynard noted, the challenges facing radiologists today are great. The day-to-day practice of radiology is evolving at an ever-increasing pace. Radiologists must be "part of the developing systems," he stressed, noting that those who continue to learn are best prepared in times of great change. "History has shown that we are up to the task," concluded Dr. Maynard, "our future is bright."