Acute appendicitis: CT and US correlation in 100 patients.

PURPOSE: To compare the accuracy of computed tomography (CT) and ultrasonography (US) in the diagnosis of acute appendicitis.

MATERIALS AND METHODS: One hundred consecutive patients were examined with US and CT, and the results, independently reported, were correlated with surgical and histopathologic findings (69 patients) and data from other laboratory and clinical follow-up (31 patients).

RESULTS: Fifty-four patients had acute appendicitis; 46 patients did not. Analysis of the data for CT and US, respectively, revealed sensitivity, 96% versus 76%; specificity, 89% versus 91%; accuracy, 94% versus 83%; positive predictive value, 96% versus 95%; and negative predictive value, 95% versus 76%. In the 46 patients without appendicitis, an alternative diagnosis was made with CT in 22 patients and with US in 15. CT scans showed abscesses and/or phlegmons in 28% of patients with appendicitis versus 17% at US. Results of CT and US were discordant in 20 patients; CT findings were correct in 17 and US findings in three.

CONCLUSION: CT is more accurate than US in diagnosis of acute appendicitis.