Intravenous Versus Rectal Contrast in CT Imaging for Abdominal Gunshot Wounds

CT imaging with rectal contrast historically has been a useful tool to help identify potential colon/rectal injuries; however, recent trends have shown less utilization of rectal contrast, in favor of IV contrast CT imaging alone. A retrospective review of patients with abdominal gunshot wounds was carried out to compare the two CT imaging techniques. An analysis of patients with colorectal injuries was conducted. Patients with IV contrast had a sensitivity of 84% and specificity of 96.8%. The PPV was 87.5% and NPV was 95.8%. In the IV and rectal contrast group, the sensitivity was 88.9% and specificity was 90.5%. The PPV was 80% and NPV was 95%. The proportion of missed injuries between the two was not statistically significant, p=0.18. The study suggests that while CT imaging with rectal contrast confidently identifies colon/rectal injuries, there are often secondary findings that will correctly prompt surgical exploration.