MEDICAL IMAGING PROBLEMS: Better--and better access to--scanning technology lets doctors hunt for rare and serious internal injuries, but is it worth exposing so many patients to radiation to find the rare cases? Image: ISTOCKPHOTO/TROUT55
As medical imaging technology has increased in sophistication and accessibility over the past decade, it is little wonder that the number of scans has also been on the rise.
Conflicting reports have emerged about whether these additional tests are having a commensurate impact on diagnosis—and cure—rates. In fact, a new study shows that for life-threatening injuries, a threefold increase in the number of computed tomography (CT) and magnetic resonance imaging (MRI) scans in emergency rooms has not resulted in an improvement in useful diagnosis.
On the ground, in hospital wards, however, doctors know that the scans can quickly help them see things that other tests cannot. "These CAT scans are way better than the x-rays," says Frederick Korley, an assistant professor of emergency medicine at Johns Hopkins University School of Medicine and co-author of the new study. New CT scans can offer rapid and detailed information about a patient that extensive x-rays, physical examination and observation are often hard-pressed and slower to reveal.
Although Korley and his colleagues had expected to find an increase in the use of these advanced imaging scans in 2007 than in 1998, "the increase was definitely more than we had anticipated," he says. Their study, which was published online October 5 in JAMA The Journal of the American Medical Association, analyzed nationwide hospital data sampled 65,376 injury-related emergency room (ER) visits between 1998 and 2007.
The researchers found that in 1998 a person admitted to an emergency department with an injury had about a 6 percent chance of having a CT or MRI scan. In 2007 that number had jumped to 15 percent. Life-threatening conditions were uncovered by these scans in 1.7 percent of the sampled 1998 ER visits and about two percent of those sampled in 2007. The most dramatic usage increase occurred between 2003 and 2007, during which time the percentage of injured patients who received CT or MRI scans almost doubled.
"It is concerning," Korley says of the trend, but simply based on their analysis, he says, it is not clear that the current imaging rate constitutes "an overuse" of the technology.
Other researchers who have been following and working in the field were not surprised by the study's results. Joshua Broder, an associate professor of emergency medicine at the Duke University Medical Center who was not involved in the new research, is also "worried about the trend," he says.
Many observers, he notes, see these large increases in diagnostic imaging and say, "'What the heck are these people doing? They're just scanning everybody,'" Broder notes. But the view from the inside is much more complicated.
When an emergency physician faces a patient with severe and possibly life-threatening injuries, that doctor often needs to make speedy decisions about what tests to order.
"Not every single person needs a test," Korley says of the scans. But with scaling back on detailed imaging tests "will come a potential small miss rate."
Some severe injuries, such as a crushed aorta, will likely be missed by x-rays and physical examinations. Although many of these instances, including aortic injuries, are rare, trauma patients who have them—usually as a result of a rapid deceleration injury, such as car crash or large fall—face a high chance of dying if the condition is not rapidly diagnosed. And just the possibility of discovering such an otherwise hard-to-find but severe internal injury, Broder says, is often enough to prompt a physician to order scans.
"One of the main motivators for doing all those scans is to hunt for that needle in the haystack," he says. "No physician wants their patient to die because they didn't find an injury." And aside from ethical and moral concerns, he notes, underdiagnosis is "a significant source of liability."