The aim of this study was to evaluate findings on CT colonography (CTC) in patients with diverticular disease. In a retrospective analysis of 160 consecutive patients, who underwent CTC and conventional colonoscopy (CC), patients with diverticular disease were retrieved. The CTC images were compared with CC and, if possible, with pathology. Findings on both 2D and 3D images are illustrated with emphasis on diagnostic problems and the possible solutions to overcome these problems. Several aspects of diverticulosis were detected: prediverticulosis (3%); global (55.6%); and focal wall thickening (4%) caused by thickened haustral folds, fibrosis, inflammation and adenocarcinoma; diverticula (52%); pseudopolypoid lesions caused by diverticular fecaliths (39%); inverted diverticula (1.2%); and mucosal prolapse (0.6%). Solutions to overcome pitfalls are described as abdominal windowing, content of the pseudopolypoid lesion, comparison of 2D and 3D images, prone–supine imaging and the aspect of the pericolic fat. In this series there were equivocal findings in case of mucosal prolapse (0.6%) and focal wall thickening (4%). Diverticulosis is a challenge for CTC to avoid false-positive diagnosis of polypoid and tumoral disease. Knowledge of possible false causes of polypoid disease and comparison of 2D and 3D images are necessary to avoid false-positive diagnosis. In case of equivocal findings additional conventional colonoscopy should be advised whenever a clinically significant lesion (≥1 cm) is suspected.
