Perceptive errors in CT colonography

Published results to date have indicated a good per patient sensitivity of computed tomographic colonography (CTC) for colorectal cancer and for polyps measuring 10 mm or more together with a very good specificity. Sensitivity and specificity for polyps in the range of 6-10 mm are moderate. These results, however, can be achieved only with meticulous attention to technique including adequate colonic distention, and acquisition of supine and prone thin-section computed tomographic (CT) images. Moreover, there is a significant learning curve involved in the interpretation of CTC studies, with performance statistics improving with operator experience. Radiologists must be comfortable in reporting directly from workstation monitors and have access to and be familiar with software for multiplanar and endoluminal reconstructions. In addition to maximize polyp detection and minimize false positive results, reporting radiologists must have a working knowledge of normal colorectal anatomy and pathology on CTC and be familiar with potential pitfalls in interpretation. Besides the description of several possible causes for perceptive errors, also a literature search of perceptive errors in CTC is included in this paper.