Advances in DIGITAL MAMMOGRAPHY
Long-awaited clinical trials are now underway
By Scott Hatfield
Digital mammography is entering a new phase with recent technological advances, including a recent submission for 510k approval to the Food and Drug Administration (FDA) to market a full-field digital mammography system. With the clinical reality of digital mammography now in sight, one noted developer said that it represents the “great equalizer” for bringing all radiologists up to a high skill level.
Trex Medical submitted clinical data on more than 500 women who had both a conventional film-screen mammogram and a digital mammogram. Six independent radiologists read each set of mammograms in order to assess “substantial equivalence” between the digital and conventional mammograms.
The project’s details were given by Trex Medical’s CEO and President Hal Kirshner during a special presentation at the 83rd Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA) where he made the official announcement.
“Breast specialists want this technology, but there is also a sophisticated and eager patient population who anticipate the benefits of digital imaging,” he said.
For those who attended the session, the announcement marked a high point in the development of full-field digital mammography that has the backing of several initial projects from the National Institute of Health and the Department of Defense (DOD), which include the investigation of telemammography.
Patients who may benefit are under clinical evaluation at sites such as Sunnybrook Health Science Centre in Toronto, Ontario, Canada. At Sunnybrook, digital mammography pioneer Martin Yaffe, PhD, senior scientist in Cancer Imaging Research, has just started clinical trials with the Fischer Imaging full-field digital mammography unit that was recently upgraded with “an improved detector technology that provides sharper images.” Dr. Yaffe has logged 12 years experience in digital mammography research.
Although the full-field digital mammography clinical trials were to begin about a year ago, Dr. Yaffe told ADVANCE there was a delay because the new technology (Fischer’s digital detector) offered the research images with better resolution.
This week, Dr. Yaffe and colleagues will begin two concurrent clinical trials, including women 40 years and older. One trial will include 200 women whose physicians have felt a lump in their breast during an examination, but a conventional mammogram did not show an abnormality. A second trial will include 100 women who have had a conventional mammogram that may or may not have shown an abnormality, however their dense breasts limit what radiologists can see on the mammogram.
Already, Dr. Yaffe believes that digital technology will benefit women, especially those with dense breasts. Digital mammography, offering image manipulation capabilities, will allow radiologists to see through the dense tissue better and view any potentially cancerous areas.
The verdict is still out, however, on digital mammography’s effectiveness over conventional film/screen mammography, Dr. Yaffe said. A multi-institutional trial is expected to begin this month, said Dr. Yaffe, who noted that Sunnybrook is one of the eight clinical sites that received patient funding for the pilot project.
Mammography professionals are expected to benefit since digital mammography will allow colleagues to consult with one another via telemammography. Another benefit will be computer-aided breast cancer diagnosis, where computer software surveys the images, identifies suspicious patterns and, alerts the radiologist.
Telemammography is a priority of NASA, which has joined with the Cleveland Clinic to study the use of satellites and high-speed digital transmissions to provide mammograms to women in regions of the United States where physicians who specialize in diagnosing breast cancer are scarce. NASA Lewis Research Center in Cleveland, Ohio, has been performing pioneering research into satellite telemedicine, especially through the use of its experimental Advanced Communications Technology Satellite (ACTS), which is the satellite being used for the telemammography study.
At present, researchers at the Cleveland Clinic and the University of Virginia are comparing mammograms that are digitally transmitted via NASA satellites to standard X-ray mammogram films. In all, they’ll examine 100 cases–50 that show malignancy and 50 that do not. This section of the study will be performed blind, meaning the mammographic readers will not know the true diagnosis prior to seeing the scans.
The second phase of the study will involve performing “real-time” satellite-transmitted mammograms on a selected number of patients. Real-time transmissions will allow women at remote sites to receive a relatively immediate diagnosis instead of waiting days for results. That way, any recommended follow-up tests can be performed immediately, eliminating the need for a second visit to the doctor for those tests.
Matthew Freedman, MD, MBA, associate professor and clinical director of the division of imaging science and information system, department of radiology, Georgetown University Medical Center in Washington, D.C., agrees that telemammography is one of digital mammography’s advantages. He should know since his facility was one of the investigational sites for the U.S. Army Medical Research and Material Command’s digital mammography project, which borrowed technologies from the DOD, Central Intelligence Agency and NASA. Georgetown University Medical Center was one of the clinical sites for the trials that used a Fuji computed radiography (CR) system to transmit full-field digital mammography scans around the world.
“We were able to transmit images of the same format that we used for digital mammography around the world; and we also transmitted digital mammograms to research colleagues in different parts of the world,” Dr. Freedman recently told ADVANCE. “We showed that it was feasible.”
Although the initial full-field digital mammography project got underway in 1991, Dr. Freedman explained that at this time the digital images “were not good enough.” Through refinements, however, five years later his same research group presented images that are comparable to film/screen mammography, he said.
The small-scale clinical trial finished last November, but Dr. Freedman said that the clinical progress of the 134 women involved is being followed by his staff to ensure there were no cancers missed. Of the women studied with both digital mammography and the conventional exam, 24 were diagnosed with cancer. The project’s final analysis will be done later this year, he added.
“It has been shown in a small group of patients that digital mammography is equivalent,” Dr. Freedman emphasized. “The same work needs to be done in a large number of patients; the reason is that conventional mammography is so very good that you need to be certain that the new method is equal if not better before you implement this on a wide scale.”
Still, Dr. Freedman believes that digital mammography will become routine within two years. “I think in two years there will probably be at least one place in each major city that has it,” Dr. Freedman said.
Scott Hatfield is the senior industry editor at ADVANCE.
‘How-To’ Guide for Teleradiology
The growth in teleradiology, a specialty of telemedicine, is attributed to the emergence of managed care and the subsequent need to perform radiologic services more cost-effectively.
Developers have reported the technology behind teleradiology allows a medical center to interpret images and provide consultation for many networked sites, increasing the cost-effectiveness and overall access to quality health care.
Radiologic science professionals who want more information on the subject can turn to the recently released Handbook of Teleradiology Applications. The paperback book was produced in response to a need for a “how-to” guide for those who want to set up a teleradiology system.
The handbook, released at the 83rd Scientific Assembly and Annual Meeting of the RSNA in 1997, is presented in a nontechnical format. It features a compilation of case studies, covering six different teleradiology settings.
Lt. Col. Miguel J. Rivera, MD, from the Madigan Army Medical Center, Ft. Lewis, Wash., shows how the military is on the cutting edge of teleradiology development. Gary D. Marano, MD, and Samuelo J. Jerandi of Radiological Consultants Association discuss the challenges of operating a frame-relay network to offer radiologic services to remote corners of rural West Virginia. In contrast, Johnson B. Lightfoote, MD, describes the application of teleradiology within the urban sprawl of Los Angeles and explains how professional teleradiologists, dubbed “night hawks,” provide imaging services to local hospitals during nonbusiness hours.
Further, Edmund A. Franken, Jr., MD, notes the advantages and disadvantages of using teleradiology within the University of Iowa, Iowa City, medical environment. The operation of Team Health, the largest teleradiology practice in the nation, is described by Donald W. Durrance, MD, and system managers Lisa Ward and Greg Smith. Also, a glimpse of the future of teleradiology is given by James H. Thrall, MD, from Massachusetts General Hospital, Boston, as he discusses the practice of international telemedicine.
Reviewed by radiology professionals active in the advancement of electronic communication, the handbook explores both benefits and pitfalls in its timely look at teleradiology’s impact on the field of radiology.
* The new publication is available for $12 and can only be purchased through the RSNA learning Center. Call (630) 368-3753 to place an order.
From RSNA reports