Role of magnetic resonance imaging in evaluation of perianal fistulas

Background: Perianal fistula is a common disorder that often recurs because of infection that was missed at surgery. Preoperative MR imaging can help to prevent recurrence. The purpose of the study was, in this article we study the various types of perianal fistulas with MR imaging and study the usefulness of MR imaging in delineating the primary tract and complications of perianal fistula.Methods: We studied MRI images of 35 patients with different types of perianal fistulas. MR imaging were performed on 1.5-T magnet MR system (Siemens magneto Essenza). Imaging was performed with multiplanar T1-weighted, T2-weighted and PDFS sequences.Results: Total 35 patients were studied, out of which 18 (51%) patients showed grade 1 (simple linear intersphincteric fistula), 5 (14%) showed grade 2 (intersphinc¬teric with abscess or secondary tract), 6 (21%) showed grade 3 (transsphincteric), 5 showed grade 5 (14%) (transsphincteric with abscess or secondary tract in ischiorectal or ischioanal fossa) and none (0%)showed grade 5 (supralevator and translevator).Conclusions: MR imaging provides precise location of the fistulous track, and its relationship to pelvic floor and the sphincter complex and helps in the identifi¬cation of secondary tracks and abscesses.