Computed tomographic (CT) colonography is a potentially powerful screening tool for colonic polyps and carcinoma. This new radiologic examination integrates volumetrically acquired data from helical CT with computer graphic software to generate two- and three-dimensional images of the colon. Before CT data acquisition, the patient is required to undergo certain preliminary steps to produce a maximally diagnostic study. Fundamental to the performance of high-quality CT colonography examinations is a completely cleansed colon and a well-distended colon, thus allowing for optimum sensitivity and specificity for polyp and cancer detection. An incompletely cleansed colon may be the cause of false negatives and pseudopolyps. Poor distention of the colon causes missed lesions and may simulate an annular carcinoma [1]. Current CT colonographic protocol requires scanning in supine and prone positions so that segments of colon with poor cleansing or collapse in one position can be reevaluated in the opposing position.