Breast MRI: An Imaging Center Opportunity to Raise Bar of Care
New guidelines from the American Cancer Society [1] recommending annual breast MRI for high-risk women are expected to result in significantly expanded demand for the study. Robert Smith, director for screening at the American Cancer Society, estimated that the new guidelines would add between 1 million and 2 million women a year to the number who should have breast MRI in the United States, according to an article in the New York Times. [2] In order to participate in the delivery of care, imaging centers must institute stringent new technical standards, invest in MR-compatible biopsy equipment, initiate training for radiologists and technologists, and, in some cases, implement more empathic patient interaction protocols. Even before the new guidelines were released in March, ProScan Imaging (PSI), a Cincinnati-based network of 25 freestanding imaging centers in 11 Eastern states and one of the largest teleradiology providers in the world, reported a threefold increase in the number of breast MRs read via teleradiology in the past year and 10 of its centers had already begun providing the examination. Stephen J. Pomeranz, M.D., CEO and medical director of PSI, has read approximately 7,000 breast MRs during the past five years and was not at all surprised by the announcement of the ACS’s new recommendations. “I have had the opportunity, first-hand, to appreciate the power of breast MR, especially in women who have tougher breasts to evaluate on x-ray,” Pomeranz said. The Patient Pool In addition to imaging women with the high-risk characteristics described in the new ACS guidelines, Pomeranz has promoted breast MR as an important tool in: breast cancer staging, imaging younger women with dense breasts, imaging small-breasted women with dense breasts, imaging women with indeterminate mammograms over a period of time, and imaging women with breast implants Breast MR plays a particularly valuable role in staging breast cancer patients, Pomeranz said. “One study, from the University of Pennsylvania’s Abramson Cancer Center three years ago, showed that between 24% and 27% of all women who had MR for staging actually had their treatment management changed by the MR,” he said. “That’s a big number. We’ve known for quite some time that the size of the cancer and the presence of more than one cancer are often underestimated dramatically by mammography. So this could impact a woman’s decision to have a lumpectomy or mastectomy, as well as the various types of supplemental therapy.” A new study published in the May issue of the Archives of Surgery found that the use of breast MRI resulted in a 9.7% beneficial change in the surgical management of patients, with a 23.2% overall change. Lumpectomy was converted to mastectomy in 10 patients (8 beneficial), wider excision was performed in 21 patients (10 beneficial), and 5 patients (2 beneficial) underwent contralateral surgery. The March publication of an ACRIN study in the New England Journal of Medicine [4] also helped to build the case for breast MR in women recently diagnosed with breast cancer. Results showed that breast MR detected twice the number of cancers as mammography in the contralateral breast of women with a recent diagnosis of breast cancer. Sponsored by the National Cancer Institute and conducted by the American College of Radiology Imaging Network, the study reinforces the suggestion that breast MR should be performed on all breast cancer patients prior to treatment planning. Another category of women who may benefit from breast MR is women with indeterminate mammograms over a period of time. “We usually educate their physicians about the role of MR,” explained Pomeranz. “And, most importantly, we educate their physicians about how important MR can be in those situations where cancers can be tough to detect, the kind of in-between cases in which the woman has some moderate risk and a screening study that is just not adequate because the technology cannot overcome the limitation of the breast configuration: the size and the density. That occurs with enough frequency to make MR very important.” Breast implants provide one of the foremost indications for breast MR, as mammography can be tough to interpret because of the density of the implant, Pomeranz said. The technology is appropriate for the following implant indications: a mass, cancer, implant rupture, pain, implant getting bigger, and implant getting smaller. “There are some other areas where MR has a tremendous impact, but they are more on the research side at this point, such as looking at the response to chemotherapy or radiation, which MR does very well.” Technical Challenges Imaging centers interested in adding breast MR as a service should know that there are considerable technical challenges in performing the study, and that technologists will need to be mentored or trained carefully. “It requires a tremendous amount of coordination between the physician and the technologist, and unlike many MSK studies, it uses contrast in almost every case,” explained Pomeranz. In addition to precise timing of contrast delivery, technologists and radiologists must ensure reproducibility from one study to the next by using similar positioning and protocols, because for a study to be used in diagnosis it must appear very similar to the previous study. Patient compliance is also very important. “The study is based on the use of image subtraction,” explained Pomeranz. “To have a good subtraction, you need a very cooperative, comfortable patient who is positioned well and will stay there for the time needed to get the study done.” Pomeranz said breast MR studies average 50 to 55 minutes to acquire, but can take as little as 30 minutes and as much as an hour and 20 minutes, depending on the clinical problem. ProScan Imaging (PSI) engages in continuous mentoring, shares protocols across its 10 facilities performing breast MR, and involves its most experienced technologists when the study is initially introduced at a facility. Mammographers and MRI subspecialists are both interested in reading breast MRI. The best approach, suggested Pomeranz, is collaboration between the two. “Mammographers have an incredible background in breast care, understand the morphologic side of things, and are able to integrate clinical information quite well with imaging information because they have been doing it for so many years,” he said. “And then you have the imagers who have been doing MR for quite some time. They have the understanding of the physics, the pulsing sequences, the performance of the study, the pitfalls, the artifacts, and all of the variables that go into an MR study -- which is unlike a CT or an X-ray for many of those reasons.” Pomeranz recommended that the novice breast MR radiologist be proctored on the first 25 to 50 cases. “But nothing beats getting with someone who knows and has had experience reading MR of breast itself, reading shoulder to shoulder with them, seeing how it is done,” he added. At PSI, the MR mammography reading pool is limited to a small group so the level of reading expertise is high and very specialized. “The more you see,” noted Pomeranz, “the better you are.” Until recently, Pomeranz noted, the data have shown that the specificity of MR is no greater than mammography, but the specificity of the study improves with the experience of the reader. “We have reduced the number of biopsies that are negative for cancer by about a quarter,” he said. “So we have been able to eliminate a significant number of biopsies and that number continues to gradually decline. As we have improved our knowledge base, we have decreased the number of negative biopsies, and in that way I think we have made a major contribution medically and economically. That comes after you have seen 1,000 or 2,000 cases and you begin to develop a strong pattern recognition library, mentally and visually, and really integrate the women’s health care knowledge base with the MR knowledge base.” Field Strength Remains Controversial The issue of technology and field strength continues to be controversial, according to Pomeranz. “The technical requirements really revolve more around the technologists and the understanding of the examination than anything else,” Pomeranz said. “You can perform a quality breast implant MR at any field strength; it doesn’t matter what the field strength is. It is helpful to have stronger gradients when you are doing cancer imaging, because you can scan faster. But from about .7 Tesla on up, and performed with the proper technical modifications, very high quality breast MR imaging is possible. I have even seen it performed very well in the European theater at .5 T. The study can be performed with two-dimensional imaging or three-dimensional imaging: Two-dimensional imaging appears to work better at mid-field or mid- to semi-high field, and the three-dimensional technique works better at high field.” Pomeranz said most of the 10 PSI facilities performing breast MR are high-field facilities. “We do open imaging only on what I call high-field open scanners, .7 T or 1 T and above,” he said. “The only time we’ll do low-field breast MR is for breast implant imaging.” In addition to having an appropriate scanner, centers need to consider an investment in: A breast coil that enables the imaging of both breasts simultaneously The ability to perform biopsy under MR. Otherwise patients with a mammographically occult cancer detected on MR will need to be re-scanned at a center that does offer biopsy. CAD software, if studies are to be read at the center. Both women’s imaging centers and MRI centers can participate in care delivery if approached seriously and sensitively. The MRI facility will need to become familiar with aspects of women’s health care, including forms of interaction with the female cancer patient. For women’s health centers, the challenges are primarily related to the technology and understanding how it works. Marketing the Study The primary referring physician community for breast MR includes: primary care physicians, obstetricians and gynecologists, breast surgeons, and to a lesser extent, oncologists. Marketing at PSI is performed through what Pomeranz describes as the most sophisticated and respected channel: referring physician education. He does not recommend direct consumer marketing. “By putting articles in their hands, through talking with them one-on-one, those age-old techniques of education, physician to physician, are probably the best way,” Pomeranz said. “If a patient asks a question about breast MR, we are going to give them an honest answer. But I think the best way for a patient to learn about this technology is to educate their doctor and let their doctor communicate with them as to whether it is appropriate or not.” Pomeranz believes the new guidelines provide a great opportunity for imaging centers to participate in raising the bar of care for breast cancer patients. “If we can detect more cancers and at the same time biopsy fewer women who don’t have cancer, we can, in a fiscally appropriate and responsible manner, save our agencies, insurers, and patients money by having greater specificity,” Pomeranz said. Through its teleradiology service, PSI’s radiologists interpret between 10 and 20 breast MRs a day from all over the world, from just about every type of MR equipment made. According to Pomeranz, one of the great challenges of breast MR is that no two machines are exactly alike. “They may have different field strengths, gradient strengths, protocols, software, and software versions,” Pomeranz explained. “So the real challenge is trying to integrate those into a thoughtful form of interpretation that can cross those technical boundaries.” Pomeranz has adopted the effective use of breast MR as a personal mission, and if imaging center providers require assistance with protocols and practices, Pomeranz is happy to oblige. “If they e-mail me with a question, I answer it,” said Pomeranz. “If they call me, I answer. If it’s a safety question, I answer it. Even when the studies look pretty good, we’ll make suggestions to tweak them. This is really the way medicine was meant to be practiced, with thoughtful and friendly dialogue. It’s very rewarding.”