Evaluation for Usefulness of Abdominal Sonography in Acute Appendicitis

ABSTRACT

PURPOSE: Acute appendicitis is one of the most common surgical diseases and the accuracy of diagnosis has been reported to be between 71% and 85%. In this study we tried to determine whether abdominal sonographic examination is critical to the decision to operate and whether its use is essential before surgery of patients with clinically diagnosed or suspected acute appendicitis. METHODS: A total of 552 patients with clinically diagnosed acute appendicitis from January 2000 to December 2001 were enrolled in this study. All patients underwent an abdominal graded compression sonography performed by a staff radiologist. RESULTS: A total of 535 patients (96.9%) with positive findings of appendicitis proceeded to surgery. 17 patients (3.1%) were found to have other diseases. Of the 535 patients undergoing operation, 531 (99.3%) were proved to have appendicitis by pathologic reports. The 17 patients with negative findings in sonography underwent operation or CT examination; 12 (70.6%) were proved to have appendicitis. Abdominal sonography for detecting acute appendicitis had a sensitivity of 97.8%, a specificity of 55.6%, an accuracy of 97.1%, a positive predictive value of 99.3%, and a negative predictive value of 29.4%. CONCLUSION: Abdominal sonography is therefore one of the most useful examinations in diagnosing acute appendicitis before surgery and our experience suggests that patients with clinically suspected acute appendicitis should routinely undergo abdominal sonographic examination.