Purpose: To assess the value of pericolonic findings at CT in the evaluation 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 interobserver correlation and the value of pericolonic and colonic wall findings 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 differentiate a diseased sigmoid colon from a normal one or from sigmoid diverticulosis. 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 circumferential wall thickening, target-like enhancement, and local fatty proliferation were findings suggesting colitis over diverticulitis. Wall thickening more than 15 mm, involvement of 15 cm or less, asymmetrical involvement, acute zone of transition, and homogeneous or heterogeneous enhancement were findings suggesting malignancy over colitis.
Conclusion: To render a diagnosis, the evaluation of the fat infiltration must prevail on the parietal thickening appreciation.