Utility and diagnostic accuracy of sonography in detecting appendicitis in a community hospital

Abstract

Objective: The purpose of this study was to determine the utility and accuracy of sonography in diagnosing acute appendicitis in patients with suspected acute appendicitis in a general community hospital.

Materials and methods: All reports relating to appendicitis were retrospectively obtained from archived transcription reports of nine radiologists from a geographically constrained hospital between December 1999 and December 2003 by a search on the keyword "appendicitis." These files were correlated with the histopathology reports from surgical appendectomy or findings from clinical follow-up during the same period. A survey eliciting the views of five local surgeons on the utility of sonography for the detection of acute appendicitis was also collected.

Results: Sonography reports for 667 patients (mean age, 34 years; range, 6-93 years) were obtained. Of these, a total of 174 had pathologically proven appendicitis and 145 had positive findings for appendicitis on sonography. The accuracy was 92%; sensitivity, 83%; and specificity, 95%. The positive predictive value was 86%, and the negative predictive value was 94%. Three of the five surveyed surgeons indicated they used sonography less than 25% of the time, with none using it more than 75%.

Conclusion: The sensitivity, specificity, accuracy, and positive and negative predicative values of sonography performed by general radiologists in a community hospital are comparable to statistics quoted in the literature for academic institutions. The most common error was the tendency to misclassify appendixes under 6 mm. Most surgeons surveyed stated their use of sonography would increase if sonography yielded a sensitivity and specificity of 85% or greater.