Abdominal computed tomography in the evaluation of acute and perforated appendicitis in the community setting.

Several studies report sensitivity and specificity of abdominal computed tomography scans (CT) for the evaluation of acute appendicitis as high as 98 per cent. Despite increased utilization of CT, the rate of negative appendectomy has remained constant at 10 to 20 per cent. The objective of this study was to assess the effectiveness of CT in the evaluation of acute and perforated appendicitis in an academic community-based setting. A retrospective review of 550 patient charts with International Classification of Diseases-9 (ICD-9) codes for acute and perforated appendicitis from January 2002 to October 2005 was performed. Sensitivity of CT was 87 per cent with a positive predictive value of 92 per cent. Specificity was 42 per cent with a negative predictive value of 29 per cent. Negative appendectomy rates were similar with or without CT (11% vs. 13%, respectively). Our data suggests that CT used liberally in everyday practice in a community-based setting to evaluate acute appendicitis may not have as strong of a diagnostic value as those used in protocol-driven research studies. Further prospective studies are needed to formulate criteria to better delineate the role of CT in the evaluation of acute appendicitis.