Appropriateness of Computed Tomography and Ultrasound for Abdominal Complaints in the Emergency Department

The purpose of this study was to evaluate the appropriateness of ultrasound (US) and computed tomography (CT) examinations ordered in the emergency department (ED) for abdominal complaints.

We reviewed 154 CTs and 154 US orders for appropriateness using evidence-based recommendations by the American College of Radiology. The sample was powered to show a prevalence of inappropriate orders of 25% with a margin of error of 7.5%. Findings in the final reports were compared to the initial clinical diagnosis classified in 4 categories: normal, compatible with initial diagnosis, alternative diagnosis, and inconclusive. We also evaluated the frequency in which a second imaging modality was ordered on the same visit.

A total of 135 CT and 143 US examinations had complete clinical information to allow evaluation of order appropriateness. The rate of inappropriate orders was 36.3% for CT and 84.4% for US. The final report of appropriate orders was significantly more likely to demonstrate findings compatible with the initial diagnosis for both CT (76.7% vs 20.4%, P < 0.0001) and US (38.9% vs 14.4%, P = 0.0093). Inappropriately ordered CT scans were more likely to show no abnormalities (46.9 vs 16.3%, P = 0.0001). An additional imaging order with a secondary modality was requested in 20% of the inappropriate US orders, and 8.2% of the inappropriate CT orders.

The prevalence of inappropriate examinations in the ED was 36.3% for CT and 84.4% for US. Appropriately ordered exams were more likely to yield imaging findings compatible with the initial diagnosis for both modalities.