Use of oral contrast for abdominal computed tomography in children with blunt torso trauma

Study objective We compare test characteristics of abdominal computed tomography (CT) with and without oral contrast for identifying intra-abdominal injuries. Methods This was a planned subanalysis of a prospective, multicenter study of children (<18 years) with blunt torso trauma. Children imaged in the emergency department with abdominal CT using intravenous contrast were eligible. Oral contrast use was based on the participating centers' guidelines and discretions. Clinical courses were followed to identify patients with intra-abdominal injuries. Abdominal CTs were considered positive for intra-abdominal injury if a specific intra-abdominal injury was identified and considered abnormal if any findings suggestive of intra-abdominal injury were identified on the CT. Results A total of 12,044 patients were enrolled, with 5,276 undergoing abdominal CT with intravenous contrast. Of the 4,987 CTs (95%) with documented use or nonuse of oral contrast, 1,010 (20%) were with and 3,977 (80%) were without oral contrast; 686 patients (14%) had intra-abdominal injuries, including 127 CTs (19%) with and 559 (81%) without oral contrast. The sensitivity in the detection of any intra-abdominal injury in the oral contrast versus no oral contrast groups was sensitivity_contrast 99.2% (95% confidence interval [CI] 95.7% to 100.0%) versus sensitivity_{no contrast} 97.7% (95% CI 96.1% to 98.8%), difference 1.5% (95% CI-0.4% to 3.5%). The specificity of the oral contrast versus no oral contrast groups was specificity_contrast 84.7% (95% CI 82.2% to 87.0%) versus specificity_{no contrast} 80.8% (95% CI 79.4% to 82.1%), difference 4.0% (95% CI 1.3% to 6.7%). Conclusion Oral contrast is still used in a substantial portion of children undergoing abdominal CT after blunt torso trauma. With the exception of a slightly better specificity, test characteristics for detecting intra-abdominal injury were similar between CT with and without oral contrast.