Imaging rates are increasing in EDs, fueled by growth in the utilization of CT, according to a report published in the October issue of the Journal of the American College of Radiology.

Vijay M. Rao, MD, of Thomas Jefferson University Hospital and Jefferson Medical College in Philadelphia, and colleagues aimed to study recent utilization trends of various imaging modalities in EDs.

Researchers queried nationwide Medicare Part B databases from 2000 to 2008, grouping imaging tests by modality, and then calculated utilization rates per 1,000 beneficiaries.

“Our data demonstrate fairly rapid and consistent growth of total noninvasive diagnostic imaging in EDs between 2000 and 2008,” wrote the authors. “Because the numbers refer to rates per 1,000 beneficiaries, the trends are independent of volume changes that might result from an increase in the number of beneficiaries.”

Overall imaging rates in EDs increased from 281 exams per 1,000 beneficiaries in 2000 to 450.4 per 1,000 beneficiaries in 2008, a 60 percent increase. CT rates rose 227 percent, the sharpest increase of any single modality. Ultrasound rates grew by 95 percent, though this amounted to only 9.1 accrued new studies per 1,000 beneficiaries. Radiography rates rose 29 percent. MRI and nuclear medicine increases were not given because their utilization rates in EDs were too low, according to the authors.

In 2000, CT accounted for 14 percent of all ED imaging, and by 2008, CT scans constituted 29 percent.

The results also showed that radiologists performed 96 percent of all ED imaging exams.

“Although this fact is encouraging for radiologists, it is likely that hospitals will begin to expect them to work more closely with ED physicians in the future to try and use more clinical rules and appropriateness criteria to limit imaging growth,” wrote the authors.

Researchers noted that while the results confirmed previous studies showing the growth of CT use in EDs, those studies did not
investigate growth in either radiography or ultrasound.

The authors suggested a number of possible reasons for the increase in CT use. CT has become faster and more accurate, and the indications for its use have expanded. As an example, they cited previous studies which demonstrated that preoperative CT for patients suspected of having appendicitis was an effective strategy in reducing the number of unnecessary appendectomies.

Rao et al also wrote that EDs are experiencing increasing caseloads, putting pressure on physicians to increase throughput by quickly ordering an imaging test rather than spending extended periods of time observing patients. Physicians are also under pressure to increase diagnostic certainty and avoid errors that could lead to malpractice claims, the authors observed.

“Thus, there are some logical and valid reasons for the rapid increase of CT use, but there are also some perverse reasons,” wrote the authors. “The latter unfortunately lead to increased costs and unnecessary exposure of patients to radiation and contrast material.”