Diagnostic accuracy of focused appendiceal CT in clinically equivocal cases of acute appendicitis

PURPOSE: To determine the diagnostic accuracy of modified focused appendice al computed tomography (CT) to exclude or confirm appendicitis in patients who presented with equivocal symptoms and signs of appendicitis. MATERIALS AND METHODS: One hundred patients (age range, 14-81 years; mean a ge, 30.6 years) with equivocal symptoms and signs of acute appendicitis wer e included in this prospective study. Patients were given 30 mL of diatrizo ate meglumine and diatrizoate sodium and 60 mL of sorbitol mixed in 1 L of water orally over 1 hour. CT was performed 1.5 hours after the commencement of oral contrast material administration. The criteria used for the diagno sis of appendicitis were (a) appendix greater than 6 mm in maximum diameter , (b) no contrast material in the appendiceal lumen, and (c) inflammatory c hanges in the periappendiceal fat. CT results were compared with histopatho logic findings at appendectomy. Patients with negative CT findings were fol lowed up by telephone or clinically. RESULTS: Of 100 cases, 30 were positive at CT and 70 were negative. There w ere 28 true-positive cases; two false-positive cases, one cecal diverticuli tis and one pelvic peritonitis with periappendicitis; and two false-negativ e cases, one perforated appendix and one mucosal and submucosal inflammatio n of the appendix but no transmural inflammation. Sensitivity was 93%, spec ificity was 97%, and accuracy was 96%. CONCLUSION: Focused appendiceal CT in which oral contrast material is used alone yields high levels of accuracy in clinically equivocal cases of acute appendicitis.