Preliminary estimate of triphasic CT enterography performance in hemodynamically stable patients with suspected gastrointestinal bleeding

OBJECTIVE. The objective of our study was to retrospectively evaluate the performance of triphasic CT enterography and identify causes of false-negative CT results in hemodynamically stable patients with suspected gastrointestinal bleeding. MATERIALS AND METHODS. A retrospective review of 48 patients (male-female ratio, 22:26) with suspected gastrointestinal bleeding (first-episode gastrointestinal bleed, n = 19; obscure gastrointestinal bleed, n = 29) who underwent triphasic CT enterography was performed. All patients had endoscopic, pathologic, or other imaging confirmation within 3 months of triphasic CT enterography. The sensitivity and specificity of triphasic CT enterography were calculated using pathology, endoscopy, or other imaging confirmation as the reference standard. Results were retrospectively reviewed to determine the cause of missed findings at triphasic CT enterography. RESULTS. The overall sensitivity and specificity of triphasic CT enterography for detecting gastrointestinal bleeding was 33% (7/21) and 89% (24/27), respectively. Sensitivity and specificity were higher in first-episode gastrointestinal bleed cases (42% and 100%, respectively) than in obscure gastrointestinal bleed cases (22% and 85%). In the subset of patients undergoing capsule endoscopy (n = 17), only triphasic CT enterography identified two of three bleeding sources. Triphasic CT enterography did not identify six ulcers, four vascular malformations, two hemorrhoids, a duodenal mass, and a bleeding colonic diverticulum. The missed findings at triphasic CT enterography were attributed to being CT occult (n = 9), perception errors (n = 4), and technical errors (n = 1). If perception errors are excluded, the sensitivity of triphasic CT enterography increases to 52% (11/21). CONCLUSION. Triphasic CT enterography can be a useful and complementary test in the evaluation of clinically stable patients with suspected gastrointestinal bleeding by identifying the bleeding source in one third to one half of patients. Because of the potential for perception errors, radiologists should familiarize themselves with the appearance of bleeding sources at CT enterography.