Suspected appendicitis in children: US and CT - A prospective randomized study

PURPOSE: To evaluate the accuracy of ultrasonography (US) and of abdominal computed tomography (CT) performed in addition to US in the diagnosis of childhood appendicitis. MATERIALS AND METHODS: Six hundred children with suspected appendicitis were included in a prospective randomized study. After clinical examination, the patients were randomly assigned to undergo US only (283 patients) or US with abdominal CT (317 patients). Radiologic findings were correlated with surgical, histopathologic, and clinical follow-up findings. RESULTS: Two hundred forty-four (40.7%) of all patients had appendicitis. In the US only group, US had a sensitivity of 86%, specificity of 95%, positive predictive value of 91%, negative predictive value of 92%, and diagnostic accuracy of 92%. The combination of US and CT performed in the other group yielded a sensitivity of 99%, specificity of 89%, positive predictive value of 87%, negative predictive value of 99%, and diagnostic accuracy of 93%. Analysis of data on US performed in all 600 patients and on CT performed in 317 patients revealed, respectively, sensitivities of 80% and 97%, specificities of 94% and 93%, positive predictive values of 91% and 92%, negative predictive values of 88% and 98%, and diagnostic accuracies of 89% and 95%. The overall negative appendectomy rate was 3.7%; and the perforation rate, 21%. CONCLUSION: US is valuable in the diagnosis of appendicitis in children. In inconclusive cases, performing additional abdominal CT can improve diagnostic accuracy and thereby decrease the negative appendectomy rate without an increase in the perforation rate. (C) RSNA, 2002.