CT colonography interpretation: how to maximize polyp detection and minimize overcalling

Anorectal pitfalls in computed tomography colonography

There is a wide array of pathological lesions seen in the anorectal region with CT colonography (CTC), much of which is unique to this location. Many relatively common findings in the anorectal region are typically benign, but can be misinterpreted as malignant. There are also technique-related pitfalls that can impede accurate diagnosis of anorectal findings at CTC. Understanding common and uncommon lesions in the anorectal region as well as recognizing technical pitfalls will optimize interpretation of CTC and decrease the number of missed cancers and false positives. This review will systematically cover that they key pitfalls confronting the radiologist at CTC interpretation of the anorectal region, primarily dividing them into those related to underlying anatomy and those related to technique. Tips for how to effectively handle these potential pitfalls will also be discussed.