Figure 6b. (a) True-positive diagnosis of a fistula track. Coronal T2-weighted two-dimensional turbo SE (3,427/150) MR image shows a hyperintense tubular structure in the left ischiorectal fossa that is surrounded by a hypointense rim (black arrow) and was correctly diagnosed as an extrasphincteric fistula track. The track ends in a small abscess (white arrow) in the left side of the pelvic floor. (b) False-positive diagnosis of a fistula track. Coronal T2-weighted two-dimensional turbo SE (3,427/150) MR image shows a hypointense track (large arrow) that courses to the left sphincter muscle complex. This hypointense structure was mistaken for an inactive fistula track. At surgery, only fibrosis was found. Note the detailed anatomy of the anal sphincter complex: the external sphincter muscle (arrowhead a), the puborectalis muscle (arrowhead b), the pelvic floor muscles (arrowhead c), and the longitudinal muscle in the intersphincteric space (small arrow).