Two of the major technological advances in radiology highlighted at the 2000 RSNA Annual Scientific Assembly were digital imaging, notably digital mammography, and picture archiving and communications systems (PACS). This article reviews some of the clinical and technical presentations in these growing areas.
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
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.
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
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
"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
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.
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
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
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
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
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
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
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
. 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
"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
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
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
"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
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
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
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
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