Improving diagnosis of acute appendicitis: results of a diagnostic pathway with standard use of ultrasonography followed by selective use of CT.

BACKGROUND Preoperative imaging has been demonstrated to improve diagnostic accuracy in appendicitis. This prospective study assessed the accuracy of a diagnostic pathway in acute appendicitis using ultrasonography (US) and complementary contrast-enhanced multidetector CT in a general community teaching hospital. STUDY DESIGN One hundred fifty-one patients with clinically suspected appendicitis followed the designed protocol: patients underwent operations after a primary performed positive US (graded compression technique) or after complementary CT (contrast-enhanced multidetector CT) when US was negative or inconclusive. Patients with positive CT findings underwent operations. When CT was negative for appendicitis, they were admitted for observation. Results of US and CT were correlated with surgical findings, histopathology, and followup. RESULTS Positive US was confirmed at operation in 71 of 79 patients and positive CT was confirmed in all 21 patients. All 39 patients with negative CT findings recovered without operations. The negative appendicitis rate was 8% and perforation rate was 9%. The sensitivity and specificity of US was 77% and 86%, respectively. The sensitivity and specificity of CT was both 100%. The sensitivity and specificity of the whole diagnostic pathway was 100% and 86%, respectively. CONCLUSIONS A diagnostic pathway using primary graded compression US and complementary multidetector CT in a general community teaching hospital yields a high diagnostic accuracy for acute appendicitis without adverse events from delay in treatment. Although US is less accurate than CT, it can be used as a primary imaging modality, avoiding the disadvantages of CT. For those patients with negative US and CT findings, observation is safe.