Acute diverticulitis of the cecum and ascending colon: the value of thin-section helical CT findings in excluding colonic carcinoma.

OBJECTIVE

The purpose of this study was to assess the value of characteristic thin-section helical CT findings of acute diverticulitis involving the cecum and ascending colon in excluding colonic carcinoma.

MATERIALS AND METHODS

Thin-section helical CT scans (5-mm collimation) of 19 consecutive patients with proven diverticulitis and 21 consecutive patients with surgically proven carcinoma involving the cecum and ascending colon were reviewed retrospectively. Two radiologists independently analyzed these parameters: degree of pericolic infiltration, mesenteric fluid, vascular engorgement, arrowhead-shaped wall thickening, air-filled diverticula, inflamed diverticula, and preserved enhancement pattern of involved colonic wall. Inter-observer agreement was assessed with a kappa statistical analysis, and the features that most distinguished diverticulitis from colonic carcinoma were selected with a stepwise logistic-regression analysis.

RESULTS

The two CT findings of right-sided colonic diverticulitis that most distinguished it from colonic carcinoma were inflamed diverticula and the preservation of an enhancement pattern of the involved colonic wall. Excellent interobserver agreement (kappa > 0.60) was obtained for both findings. Inflamed diverticula (kappa = 0.80) had a mean sensitivity, specificity, and accuracy for diverticulitis of 86.8%, 92.9%, and 90.0%, respectively, in differentiating right-sided colonic diverticulitis from colonic carcinoma. Preserved wall enhancement pattern (kappa = 0.70) had a mean sensitivity, specificity, and accuracy of 89.5%, 95.3%, and 92.5%, respectively.

CONCLUSION

On thin-section helical CT, an inflamed diverticula and a preserved enhancement pattern of the thickened colonic wall were the two most statistically significant CT findings of acute diverticulitis involving the cecum and ascending colon that distinguished diverticulitis from colonic carcinoma.