To evaluate the concordance of helical computer tomography (CT) staging and surgical findings in patients with acute appendicitis

Retrospective study of patients with acute appendicitis confirmed by surgery during the period from 1998 and 2004. All patients underwent a pre-operative CT scan, which was reviewed, independently and then in consensus, by three different radiologists. Slice thickness and type of contrast administrated, depended on the radiologist and patient's clinical history. The helical CT results were classified into five stages, from lesser to greater severity, and then grouped into two categories: perforated and non-perforated appendicitis. These results were compared with those at surgery. Weighted Kappa, Student’s t and Chi-Square tests were used for the analysis of concordance, differences in continuous variables and for categorical variables, respectively. P<0.05 was considered statistically significant.

A total of one hundred and twenty patients with surgically proven acute appendicitis were evaluated. The concordance of CT staging and surgical findings was weighted kappa=0.60 (95% CI: 0.50-0.70, P<0.01) which can be considered substantial. Moreover, when using the perforated and non-perforated categories, the concordance of CT scan and surgical findings increased to weighted kappa=0.66 (95% CI:0.59-0.73, P <0.01). Certain CT findings had a strongest statistical significance with perforated appendicitis.

The present study suggests that CT scan staging of acute appendicitis shows a good concordance with surgical findings, specially when perforated and non-perforated categories are considered. Therefore, helical CT may be used as a marker of severity of acute appendicitis, and might influence the therapeutic approach of these patients