Fig. 7.

MRI diagnosis of post-surgical ECF in a 65-year-old male with long-standing fistulising CD, previous abdomino-perineal resection for perianal fistulas complicated by anal squamocellular carcinoma (ASC). On T2-weighted images, the fluid-filled ECF (arrows) was seen coursing ventrally to reach the ventral EFO (arrowheads) at the site of past surgical incision, from the apex of a large T2-hyperintense mass (* in A) corresponding to recurrent ASC. Post-gadolinium fat-suppressed T1-weighted image (C) showed mucosal hyperenhancement (thin arrow) along the fistula track