Review of the relevant anatomy associated with perianal fistula. Understanding the importance of MRI in pre-operative planning, key imaging features and their clinical significance. Implementation of a standardised structured graphical synoptic reporting template for perianal fistula to enable efficient, concise and effective communication.

Perianal fistula is an inflammatory condition where there is an abnormal connection between the anal canal and the skin of the perineum. Complex fistulae have a higher tendency to recur and are therefore at increased risk of requiring repeated surgical intervention [1]. Their etiology can either be a consequence of local sepsis of the anal crypts and glands (i.e. cryptoglandular disease) or as a feature of inflammatory bowel disease (i.e. Crohn’s) [2]. Understanding the anatomy of this region is imperative for accurate identification, classification and...

The primary role of MRI is to outline all perianal fistula tracts and define their relationship to the anal sphincter. Numerous MRI imaging protocols have been advocated with common sequences including sagittal T2, T2 fat-suppressed in both axial and coronal plans angled to the anal canal with a single 3D sequence (i.e. SPACE) [5]. T2-weighted images provide suitable contrast between the hyperintense fluid within the tract and the hypointense fibrous wall of the fistula. Active fistulae are hyperintense on T2 whilst the sphincters are hypointense...

MRI has been established as the mainstay modality of imaging for pre-operative assessment of perianal fistulae. It has the ability to accurately define the fistulous tract, its extension, relationship to surrounding structures and any associated complications. Understanding the key MRI features and how they relate to the clinical management and outcome is essential to providing a clear and concise radiological report. This is essential to ensure the most appropriate surgical management is undertaken with avoidance of operative complications. Standardised template reporting coupled with graphical illustration...

Dr. Hung Dang Department of Medical Imaging Royal Adelaide Hospital Adelaide SA 5000 Email: [email protected]

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