Centers of excellence could improve mammography's quality profile

When the Institute of Medicine released its report last year on mammography, it introduced a subtle but important concept to the U.S. imaging community: the idea of breast imaging subspecialization and the use of centers of excellence to improve quality.

One year later, the idea of specialized breast imaging practices seems to be catching on. Our cover story on the topic this month found strong support for the idea that higher volumes made possible under the centers of excellence approach, in combination with other factors, can improve the quality of breast imaging practice.

Of course, breast imaging practice in the U.S. remains troubled by serious problems: a high rate of medical malpractice claims, relatively low reimbursements, and declining interest in breast imaging practice among new radiologists. But the centers of excellence concept represents a hopeful trend and a strategy that could help breast imaging mitigate some of its problems.

We can't say exactly how many dedicated breast imaging centers are in operation in the U.S., but one indication is the National Consortium of Breast Centers, whose membership is nearly 1000 clinics strong.

The growing interest in breast imaging centers reflects a number of factors, such as growing medical specialization, but it is mainly a consequence of advances in technology.

A couple of years ago, for example, digital mammography sales outstripped conventional film mammography sales, at least in dollar volume. The higher cost of the digital equipment, and presumably, higher throughput, will push higher per-radiologist volumes. Higher costs for compliance with the Mammography Quality Standards Act will likely also influence volumes. Passage of that law in 1992 forced out many marginal facilities and improved mammography screening quality.

Teleradiology will open more doors to centralization. Access to screening mammography is a perennial issue, but the time has come for us to recognize that the system has evolved over the past decade. With today's technology, maintaining a physical link between image collection and interpretation is becoming less important.

Practical and economic factors figure in as well. Centralized facilities tend to make better use of physical resources such as equipment and space, and they can allow better workflow.

Once these centers of excellence are established, what can we expect? Breast imaging expert Dr. Laszlo Tabar and other European experts (including Dr. Nick Perry, director of breast screening at St. Bartholomew's Hospital in London and a source for the Institute of Medicine report) argue persuasively that higher interpretation volumes increase expertise. Under the MQSA, the minimum number of interpretations for a breast imager is 480 per year. In fact, the IOM found that 40.4% of mammograms in the U.S. are interpreted by radiologists who read between 2000 and 5000 per year; nearly that many (36.8%) are interpreted by radiologists who read more than 5000 per year (see chart on page 33).

Besides volume, the other factors promoting better quality in centralized reading situations include auditing, peer review, and data collection programs that are more extensive and powerful than those available in peripheral settings. While it is true that data from multiple institutions can be aggregated, the process is probably easier under a center of excellence approach.

What all of this suggests is a shift toward models of breast care that have proved successful in Europe. It's a natural evolution and one that bodes well for the future of breast imaging in the U.S. It's also useful to note that this is being accomplished under existing regulatory structures, a point that needs to be remembered as we move toward the 2007 reauthorization of the MQSA.