[CT colonography: pathologic findings and pitfalls].

Thin-section multidetector-row computed tomographic (MDCT) colonography is a powerful tool for detection and classification of colonic lesions. It is based on a helical thin-section (0.75-2 mm) CT dataset of the cleansed and air-distended colon. 2D and 3D projections are prepared and used for image interpretation. Evaluation of CT colonography datasets requires correct perception and interpretation of colonic lesions and filling defects. Various criteria are needed for correct interpretation of filling defects and differentiation between genuine lesions and artifacts. Such defects are characterized by their morphology, their structure, the absorption of contrast medium and their mobility. Knowledge of the morphologic and attenuation characteristics of common colonic lesions and of artifacts is essential for the correct interpretation of a filling defect. This review article summarizes the main imaging features of polyps, diverticula, lipomas, and carcinomas and also of common pseudolesions of the colon.