Different types of posterior complex anal fistulas from our cohort, as seen on coronal contrast-enhanced fat-suppressed T1-weighted images with different corresponding sections. (A) The suprasphincteric anal fistula with multiple branches in the deep intersphincteric horseshoe tracts and right ischiorectal fossa. (B) The low transphincteric anal fistula with right ischiorectal fossa abscess and deep intersphincteric horseshoe tracts, extending along the left combined longitudinal muscle into the supralevator area of the rectal muscle. (C) The high transsphincteric anal fistula in the left puborectal muscle with up spread supralevator into the pelvirectal space. The arrows are pointing at the IO. The triangles represent deep branches. IO = internal opening.