Credit or Blame? CT Propels Imaging in the ED

Twitter icon
Facebook icon
LinkedIn icon
e-mail icon
Google icon
 - CT

EDs are feeling the strain—more patients, fewer resources and ubiquitous closures—and matters are only getting worse. Expanded coverage under the Patient Protection and Affordable Care Act of 2010 and continued spending cuts, the weak economy and lack of insurance coverage will more than likely increase patient demand. On the imaging end, emergency physicians are in the crosshairs, derided as some of the most profligate utilizers of imaging.

For many ED physicians, these figures signify distraction more than doomsday. They point out that increasing volume and decreasing resources have become the baseline, a norm dating back a decade of emergency medicine, if not longer. "The trend is not a major problem because [the shortage of resources] drives quality and efficiency in high-volume EDs," remarks Martin Gunn, MD, an assistant professor of body imaging and emergency radiology at the University of Washington School of Medicine in Seattle.

The medical, economic and political pressures that have shaped ED imaging in the last quarter century are subtle; the result is not. "There is no question that CT is the workhorse of the ED. Combined with ultrasound, it accounts for roughly 90 percent of advanced emergency imaging, and it's likely to stay that way for some time," says John Thomas, MD, a radiologist at the University of Alabama at Birmingham who authored a comprehensive survey of ED practices in the last five years. Statistics cry out that emergency medicine is in need of critical care, but as ED physicians are quick to point out, the data belie the startling advancement of emergency medicine, with CT at the center.

ED imaging: A brief history

Annual ED visits have surged 23 percent over the last 15 years (Centers for Disease Control and Prevention). During that same time, the number of urban EDs fell by more than one-quarter, while the total number of EDs in the U.S. fell by more than 12 percent (CDC; JAMA, 2011). Radiology has played a critical role in keeping up with growing demand: CT utilization in the ED spiked 330 percent from 1996 to 2007, according to a study published in the September issue of Annals of Emergency Medicine. The surge in CT studies grew 11 times faster than the rate of ER visits. Just 3.2 percent of ED patients received CT scan in 1996—13.9 percent of patients had one in 2007 (that's one of every seven patients and also means that one quater of all CT exams are done in the ED).

Neuroimaging accounts for about half of this growth, while abdominal and cardiac CT exams are also on the rise. "We were surprised at the number of EDs performing triple-rule-out scans," a single CT to rule out coronary artery disease, pulmonary embolism and aortic dissection, which was about one-fifth of EDs, according to Thomas' 2008 study. Meanwhile, MRI is performed in less than 1 percent of ED visits, with an equally negligible rate of growth.

Critics have attacked the growth of CT in the ED from a variety of angles. An October 2010 study in Journal of the American Medical Association questioned why the 250 percent growth in CT was accompanied by the diagnosis of only 15 percent more life-threatening conditions, and why abdominal CT is on the rise despite no change in the prevalence of significant abdominal conditions. With a parallel uptake in scrutiny over costs and radiation exposure in the last decade, ED physicians are having to answer to medical, political and public interrogation.

"What often gets forgotten in these debates—the reason we have these issues over CT utilization—is that it's such a tremendously useful tool and so greatly improved our ability to to diagnose and treat our patients," says Aaron Sodickson, MD, PhD, director of emergency radiology at Brigham and Women's Hospital in Boston. The September Annals study pointed to a 50 percent drop in hospital admissions following a CT scan in the ED from 1996 to 2007. Sodickson sees CT ordering as having a low threshold; physicians have become dependent on it.

From the perspective of the clinician, this dependence is in many ways understandable. As emergency physicians become forced to think about patient care in the scale of seconds, CT enables accurate diagnoses, fast. "If a patient comes into the ED with abdominal pain, it could be one of 50 diagnoses. CT is often used because it casts a broad net to see what's going on," Sodickson continues.

Thomas points out, "A good portion of tests ordered by ED physicians are requested by the specialists they