Computed tomographic features of appendiceal serositis in pelvic inflammatory disease: Comparison with pathological findings

Objective: The purpose of this study was to describe the computed tomographic (CT) features of the appendiceal serositis in women with pelvic inflammatory disease and to compare these with the pathological findings. Methods: Appendiceal serositis was pathologically evaluated in patients with pelvic inflammatory disease who underwent surgery within 3 days of computed tomography. On retrospective review of CT findings, each appendix was evaluated for the following characteristics: location relative to the cecum, maximal diameter, morphology of wall thickening, contrast enhancement, and presence of appendicolith and cecal wall thickening. The presence of fatty infiltration of the periappendiceal fat, mesentery, and omentum was evaluated. The presence of pelvic abscess or ascites, lymph nodes, and paralytic ileus was noted. Results: On pathological review, 10 patients were shown to have appendiceal serositis: mild serositis in 3 patients, moderate in 4, and severe in 3. The maximal appendiceal diameter ranged from 5.4 to 8.9 mm (mean diameter, 7.1 +/- 0.9 mm). Diffuse wall thickening with collapsed lumen was detected in 6 patients. Focal wall thickening with intraluminal gas bubbles or an air-fluid level was detected in 4 cases. Peripheral rim enhancement of the appendix was detected in 3 patients with focal wall-thickened appendix. There was no association between the feature of appendiceal wall thickening and the pathological severity of scrositis. Mesenteric fatty infiltration was detected in 5 patients and omental fatty infiltration in 3 patients. Fatty infiltration of the mesentery and omentum was more commonly presented in patients with severe serositis. Pelvic abscesses, including pyosalpinx, were detected in 7 patients; a small amount of free fluid was seen in 8 patients. Conclusions: The CT findings of appendiceal serositis are diffuse or focal wall thickening without severe distension, common association with mesenteric fatty infiltration, and pelvic abscesses.