Perforated and nonperforated appendicitis: Defect in enhancing appendiceal wall - Depiction with multi-detector row CT

Purpose: To retrospectively evaluate the accuracy of multi-detector row helical computed tomography (CT) with intravenous contrast material and without oral contrast material for depiction of perforated appendicitis. Materials and Methods: This study was approved by the institutional review board: informed consent was waived. CT images in 102 patients (60 male patients, 42 female patients; age range, 4-82 years; mean age, 37.3 years) with surgically and pathologically proved appendicitis who were examined between January 2000 and December 2002 were retrospectively reviewed. Original transverse sections at 3- or 2-mm collimation and 1.5- or 1.0-mm intervals were viewed by using cine mode observation. Two independent observers evaluated five specific findings (defect in enhancing appendiceal wall, abscess, phlegmon, extraluminal air, and extraluminal appendicolith). Sensitivity, specificity, and accuracy of the specific findings in the diagnosis of perforated appendicitis were evaluated. Results: Perforated appendicitis was present in 40 patients, and nonperforated appendicitis was present in 62 patients. A defect in the enhancing appendiceal wall was present in 38 patients in the perforated group. Two patients in the nonperforated group had false-positive findings for a defect in the enhancing appendiceal wall. Sensitivity, specificity, and accuracy of this finding in the diagnosis of perforation were 95.0%, 96.8%, and 96.1%, respectively. Sensitivities for abscess, extraluminal air, and extraluminal appendicolith were 37.5%, 22.5%, and 32.5%, respectively. These three findings were not found in patients with nonperforated appendicitis. Phlegmon was seen in 16 patients in the perforated group and in three patients in the nonperforated group. Sensitivity, specificity, and accuracy of phlegmon in the diagnosis of perforation were 40.0%, 95.2%, and 73.5%, respectively. Conclusion: Multi-detector row CT allows an accurate (96.1%) diagnosis of appendiceal perforation by the depiction of a defect in the contrast material-enhanced appendiceal wall.