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

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.

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.

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%.

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.