Figure 4: High trans-sphinctericgrade 4 fistulous tract. (arrow) extending from the left side of the perianal skin to the ischioanal fossa, passing anteriorly, superiorly, and, arching medially, penetrating both external and internal anal sphincters ending at posterolateral wall of the anal canal. (arrowhead). There is a small intersphincteric abscess measuring 1. cm in all diameters. (asterisk). (a and b) Coronal STIR images. (c and d) Axial STIR images.