Predictive value of sphericity index and other multidetector computed tomography findings in perforated acute appendicitis

BACKGROUND: Early radiological prediction and diagnosis of perforated acute appendicitis remain controversial. In the current study, it was aimed to examine the predictive value of multidetector computed tomography (MDCT) findings in perforated acute appendicitis. METHODS: The patients (n=542) who underwent appendectomy between January 2019 and December 2021 were retrospectively evaluated. The patients were divided into two groups as non-perforated appendicitis and perforated appendicitis. Preoperative abdominal MDCT findings, appendix sphericity index (ASI) scores, and laboratory findings were evaluated. RESULTS: The sample consisted of 427 cases in the non-perforated group and 115 cases in the perforated group, with a mean age of 33.88±12.84 years. The mean time until admission was 2.06±1.43 days. Appendicolith, free fluid, wall defect, abscess, free air, and retroperitoneal space (RPS) involvement were all found to be significantly higher in the perforated group (P<0.001). The mean long axis, short axis, and ASI values were found to be higher in the perforated group (P<0.001; P=0.004; and P<0.001, respectively). C-reactive protein (CRP) was found to be significantly higher in the perforated group (P=0.008), but the mean white blood count was found to be similar between the groups (P=0.613). Among MDCT findings, free fluid, wall defect, abscess, high CRP, long axis, and ASI were observed to be predictive values for perforation. According to receiver operating characteristic analysis, ASI had a cut-off value of 1.30, a sensitivity of 80.87%, and a specificity of 93.21%. CONCLUSION: MDCT findings, namely, appendicolith, free fluid, wall defect, abscess, free air, and RPS involvement are significant findings for perforated appendicitis. With a high sensitivity and specificity, the ASI appears to be a key predictive parameter for perforated acute appendicitis.