As researchers continue to compare digital mammography with conventional screen-film mammography in the Digital Mammography Imaging Screening Trial (DMIST), one known effect is the positive impact of digital imaging on workflow. This is particularly important today, since an aging population is causing an increase in demand for mammography services, with many breast imaging centers experiencing large backlogs of mammography appointments. As a result, workflow efficiency becomes critical in accommodating this additional procedural volume.

Even though digital mammography has the ability to generate a more efficient and less costly service, many breast imaging centers have found that it is easier to make the transition to a filmless environment in a more gradual fashion. This is mainly due to the fact that making a complete conversion to digital mammography presents its own set of workflow challenges.

GRADUAL TRANSITION

Alan Semine, MD, is medical director, Women's Imaging Center, Newton-Wellesley Medical Center, Newton, Mass. He says, "There is no doubt that digital mammography allows you to be more efficient in terms of patient throughput, and that is why we are looking at switching soon to a completely digital environment. Digital technology will allow us to grow without having to expand space or the number of mammography units." At the same time, Semine has recognized the benefits of easing into a digital environment. Currently, the Women's Imaging Center has one digital room and six analog rooms; in the next few months, its goal is to convert two more of the analog rooms into digital rooms.

Semine believes that it makes sense to start out with one digital unit, identify problems that might arise, and then develop solutions before acquiring additional systems. "With these types of transitions there are always delays, kinks, and psychological glitches in the beginning," he says. "We will have worked through most of these problems by the time we have converted to a completely digital environment."

One of the specific areas that Semine is working on with his vendor is enhancing communication between the radiologist and technologist in the digital environment. "Communication between the radiologist and the technologist is critical. With analog systems, this is handled when a radiologist circles an abnormality on the film and then asks the technologist to obtain additional views," Semine says. "With a soft-copy environment, this communication channel is not clearly established." The Women's Imaging Center is consulting with its vendor on this problem by setting up a system whereby soft-copy images are sent back from the radiologist to the technologist for direct viewing at the acquisition workstation. In this way, the technologist can immediately know if additional views are needed, rather than having to go to the radiologist's office to obtain this information.

TWO FOR THREE

Workflow efficiencies have led many breast imaging facilities undergoing expansions or renovations to add digital mammography. A major expansion of Dartmouth-Hitchcock Medical Center in Lebanon, NH, included the construction of a satellite radiology department and a renovation of the existing department. This was a major factor in making the conversion to digital mammography. According to Monte Clinton, CRA, director of radiology, digital imaging made it possible to send digital images from the satellite center to the main department without requiring radiologists to walk to the new location, which is more than 400 m away. During the planning stage for the new facility, the department considered two options to handle the expected mammography volume: install three analog mammography units (with their associated film multiloaders and wet-processing units) or buy two more expensive digital mammography units (which offered the same volume with one third less staff time and the elimination of the consumable supplies, plumbing, and maintenance required for wet processing). These advantages, along with the ability to keep the radiologist in the main department, made it logical to use digital mammography instead of analog systems. Since the satellite imaging center opened in August 2004, approximately 60 patients have been screened each day.

"One of the best things is that the technologist does not have to leave the room during the examination, and this has greatly improved productivity," Clinton says. "Our goal has been to reduce the time that a patient has to wait for a screening appointment, and these digital units have helped us accomplish this." Clinton notes that the new building has space for a third digital unit, which the department hopes to acquire in 2005.

Like Dartmouth-Hitchcock Medical Center, Covenant Health's St Joseph Outpatient Center in Milwaukee was also faced with a decision on digital mammography equipment for its new facility that opened last year. According to Cindy Ellingson, CRA, director of radiology, the center purchased one digital unit, but decided to include one analog unit, as well. "This was a new frontier for us, and many of the radiologists had never looked at digital images before, so we believed that it was best to offer both types of equipment in the beginning," she says. The center has a group of radiologists who rotate through the department instead of a designated set of mammography radiologists, which presented another challenge in terms of physician training on the new unit. Before they could read the digital mammograms, the radiologists needed about 8 hours of training on the new unit. "The radiologists, as well as the technologists, now overwhelmingly prefer the digital system," Ellingson says. She adds that some patients come to the center because of its digital mammography.

Like any institution that operates in a dual digital/analog environment or has just introduced digital mammography, St Joseph must now compare prior analog images with new digital images. In most situations, prior studies are reviewed using a film viewer located at a right angle to the soft-copy workstation. Previous films are hung in case order, allowing radiologists to review the prior images without holding them, which minimizes the inefficiencies. Obviously, when comparing digital images to prior digital images, workflow is more smooth, since retrieval from the picture archiving and communications system (PACS) archive takes only about 15 seconds.

BUDGETARY CONSTRAINTS

Economics is one of the primary reasons that many breast imaging facilities are acquiring digital mammography slowly. With an average cost of $400,000 to $500,000 for one digital system, compared to $80,000 to $150,000 for its film-based counterpart, it is easy to understand why few mammography centers have made a complete transition to filmless systems. "If you have film-based systems that are less than 5 years old, you are not going to scrap them automatically," according to Laurie Fajardo, MD, chair of the department of radiology, University of Iowa Health Care, Iowa City. "You have to amortize and replace equipment as it is needed, and I think that is the major reason people are taking things slowly."

The University of Iowa Hospitals and Clinics currently has one digital and three conventional units, with 33% of its mammography patients being screened digitally. Since the digital technology is more suitable for patients with dense breast tissue, the radiologists look at the previous year's films to see which women would benefit from digital imaging. "If we have three patients coming in per hour, it is not hard to determine which one is better suited to the digital unit," Fajardo says. The facility is also currently evaluating a digital tomosynthesis unit. "Instead of a second conventional digital unit, we may actually consider purchasing one of these tomosynthesis systems, which will not cost much more than a conventional digital machine," Fajardo adds.

Although the cost of digital units is significantly higher than that of their analog counterparts, most hospital-based women's imaging centers are quickly recognizing the value of these systems. Clinton notes that the digital mammogram serves as a key entry point into his hospital for many women. "If a patient were to have a positive mammogram and need additional examinations or treatments, we would be able to offer all the necessary services because we have a comprehensive, integrated women's health program," he says. Clinton is also quick to point out that even though the cost of digital mammography may seem high, other subspecialties within radiology have already discovered that digital radiography is effective in improving workflow efficiency. "The whole world is going digital," Clinton says, citing public predictions that the electronic medical record is likely to be in place throughout the health care delivery system within a few years.

WORKFLOW ENHANCEMENTS

Some hospitals have been so impressed by the potential cost savings that they have made complete conversions to digital mammography. Bates County Memorial Hospital, Butler, Mo, is one such institution. Introduced in January 2004, its digital unit replaced an analog unit, and it did not take long before significant efficiencies were noticed. Christi Pope, RT, RM, RDMS, director of imaging services, says, "Screening with the analog system took approximately 25 to 30 minutes, but I can now do a digital examination, including history and explanation, in approximately 10 to 12 minutes. This reduction in time has allowed me to accept walk-in patients, and I can also schedule more procedures per day."

According to Pope, the technologists' workflow is much more streamlined with digital mammography. The technologist begins by rebooting the mammography unit, which is never shut down and does not require warm-up exposures. The patient changes in the dressing room while the technologist retrieves patient information from the acquisition station, which subsequently queries the radiology information system. The technologist is not required to type in patient demographics, but does have to select the appropriate examination type. In the examination room, the technologist asks the patient for pertinent history, fills out the recommendations letter, and has the patient sign the required complaint/dissatisfaction form. After explaining the difference between digital and analog mammography, the technologist performs the procedure, checking each image before moving on to the next view. "This gives the patient respite between compressions and allows her to ask questions concerning the examination," Pope says.

The images are sent to the PACS and soft-copy workstation at the same time, as soon as the image is accepted by the technologist on the acquisition station. After the last view is taken, if the procedure is a screening examination, the patient can leave. If the procedure is a diagnostic study, the patient is instructed to wait while the images are reviewed with the radiologist. Pope notes that this discussion with the radiologist has actually served as a marketing tool. "The patients are so impressed with the system, and the fact that the radiologist is taking time discussing their procedures," she says. "These patients walk away with firsthand knowledge of the differences between the digital and analog systems."

In terms of radiologists' workflow in the digital environment, the physician simply signs in at the soft-copy workstation and receives a patient folder containing the mammographic information work sheet, recommendations letter, patient complaint/dissatisfaction form, and an addressed recall envelope. Attached is a work sheet listing the mammographic examinations that the radiologist is responsible for on the hard-copy viewer. The radiologist then chooses the correct examination on the workstation and correlates its demographics with those of the prior study's film. After dictating the report, the radiologist fills out the appropriate sections on the mammographic information work sheet and then proceeds to the next case. "The radiologist has less film and paperwork clutter, which creates a more organized, relaxed setting for image review," Pope says.

In the event of abnormal findings, a digital system allows patients to obtain images easily for outside evaluation or further treatment. The views are simply printed (for example, from an acquisition station to a digital image printer). A major advantage for the consulting physician is that these images do not need to be returned.

According to Pope, her department has noticed a decrease in recall rates since the introduction of digital mammography. She credits the magnification tool on the soft-copy workstation for allowing radiologists to be more thorough in the initial survey of a screening mammogram. "We expect the recall rates to decrease further when comparisons are digital-to-digital," Pope says.

Feedback from mammography providers offering digital imaging has been extremely positive, particularly from centers performing a large volume of mammograms. Imaging centers serving smaller populations need to weigh the fixed costs associated with the technology versus efficiency gains. In the years ahead, continued research will help determine the effectiveness of this technology. "The tradeoffs between benefit and cost," Fajardo says, "should be clearer in the near future, as data from large trials such as the DMIST study are evaluated."

Navigating the Learning Curve A full-field digital mammography unit allows Zeeshan Shah, MD, and other physicians at the Indiana University School of Medicine to zoom in, magnify, and optimize the viewing of different areas of breast tissue. Some administrators believe that one of the biggest hurdles in making the transition to full-field digital mammography is mastering the learning curve. Concerns about the time and costs involved in training radiologists and technologists to use filmless mammography units effectively have made breast centers overly cautious about entering the digital world. The mammography staff at Indiana University Hospital in Indianapolis, however, has demonstrated that these fears can be exaggerated. In early 2004, the radiologists and technologists had planned to undergo a week of training prior to unveiling their new digital mammography unit the following week. The training program was handled smoothly by the manufacturer, and everyone felt prepared to use the new system, located alongside two conventional analog rooms. What they were not prepared for on that day was the malfunction of their film processor, which meant that they could not use their analog units at all. "We had to do our entire schedule on our new digital machine even though the staff only had 5 days of training on it," Zeeshan Shah, MD, assistant professor of radiology, Indiana University School of Medicine, Indianapolis, reports. "It was a bit of a rush, but we were able to perform examinations on all of the patients scheduled for that day." Shah notes that one of the reasons that the staff was able to reach full speed so quickly on the digital system is that it is based on the same platform as their previous film-screen units, so it looks and feels similar to operate. The technologists became great admirers of the digital technology, appreciating that they do not have to leave the examination room and can check each view for technical quality before moving on to the next one. "The technologists like the fact that they can show the patient, right there, why they might have to reshoot a view," Shah says. One of the work flow issues that they first encountered was how to perform triage to determine which patients should use the digital room. The department decided that it should be handled like the other mammography rooms by offering digital mammography on a first-come, first-served basis. As increasing numbers of patients are starting to ask for digital mammograms, the staff does try to accommodate those requests. The plan is to perform annual and follow-up examinations on the digital unit if a patient's prior studies were done digitally. Since the digital unit was installed, Shah has noticed that radiologists tend to take more time viewing the images. This technology allows physicians to zoom in on, magnify, and optimize the viewing of different areas of breast tissue without having to obtain additional images. When prior studies are analog, further time is added to the review process. "It definitely takes longer comparing digital images to prior analog films," Shah says. "When we were trained in school, we compared film screens to film screens, using a magnifying glass, so naturally we are faster doing this. In the beginning, it takes a little longer reading a digital mammogram or comparing a digital image to a film image, but radiologists become used to this and it's not a huge problem. Certainly we'll all be happier when we're comparing digital images to digital images, and that won't be too far off in the future." "One of the problems is that digital and analog images look so different," he continues. "A digital image is almost twice the size of a film image, which means it takes longer to study because you have more surface area to examine. Since the contrast can be so different with digital and analog images, it's sometimes difficult to tell if a certain cluster of calcification was really there on the prior film." Shah says, "I feel that when I read things off the digital monitor, I am more thorough, because I am forced to look at every part of the image a little more closely." Shah adds that digital images make it easier to dismiss calcifications that would be questionable on an analog image, and he expects this to improve recall rates. Shah looks forward to the day when his department will be completely digital. The mammography center sees about 50 patients each day, with the majority being diagnostic cases due to the tertiary nature of the hospital. Approximately 80 additional films and screenings from satellite facilities are also viewed each day by the radiology staff. With this large volume, efficiency becomes a paramount concern. Shah says, "We recognize that, as we continue to make the transition to a digital environment, we will save money, not only by being able to take on a greater case load more efficiently, but also by consolidating equipment and space."

--Carol Daus

Carol Daus is a contributing writer for Decisions in Imaging Economics.