MRI of anal canal: normal anatomy, imaging protocol, and perianal fistulas: Part 1.

Anal complaints are very common in the general population and are caused by a variety of disorders mostly benign in nature. The aim of this article is to provide the radiologist with a detailed description of the MRI anatomy and technique, and an overview of the various diseases most commonly presenting with anal pain, by descriptions and illustrative examples of MRI features of each entity.