CT of the sigmoid colon: imaging findings and interobserver correlation

Purpose. To assess the value of pericolonic findings at CT in the evaluatio n of the sigmoid colon. Materials and Methods. A total of 210 CT examinations were retrospectively reviewed by 3 blinded radiologists. Data was analyzed to determine the inte robserver correlation and the value of pericolonic and colonic wall finding s in diagnosis of sigmoid colon pathology. Results. The interobserver correlation for pericolonic findings was: equal to or superior to that for colonic wall findings. The presence of abnormal pericolonic fat was the most sensitive (88 %) and specific (93 %) sign to d ifferentiate a diseased sigmoid colon from a normal one or from sigmoid div erticulosis. Wall-thickening was less sensitive (82 %) and specific (76 %). Findings suggesting malignancy over diverticulitis included acute zone of transition, focal fatty infiltration, and lymph nodes. Symmetrical and circ umferential wall thickening, target-like enhancement, and local fatty proli feration were findings suggesting colitis over diverticulitis. Wall thicken ing more than 15 mm, involvement of 15 cm or less, asymmetrical involvement , acute zone of transition, and homogeneous or heterogeneous enhancement we re findings suggesting malignancy over colitis. Conclusion. To render a diagnosis, the evaluation of the fat infiltration m ust prevail on the parietal thickening appreciation.