title: [Application of magnetic resonance imaging in the diagnosis of complex anal fistula].
abstract: OBJECTIVE
  To evaluate the value of magnetic resonance imaging (MRI) in the diagnosis of complex anal fistula.
  
  
  METHODS
  The preoperative digital examination and MRI with the phased-array coil were implemented for 28 patients who were clinically suspected with complex anal fistula. The final diagnosis were based on surgical findings. Outcomes of MRI and digital examination were compared with surgical results.
  
  
  RESULTS
  Twenty-five patients were diagnosed as complex anal fistula, 1 presacral cyst and 2 chronic anorectal fistula combined with perianal mucinous adenocarcinoma. All the patients were correctly diagnosed by MRI,while the patients with presacral cyst and perianal mucinous adenocarcinoma could not be diagnosed correctly by digital examination. According to the Parks classification, 3 patients were suffered from trans-sphincteric fistula, 10 intersphincteric, 5 supra- sphincteric and 7 extra-sphincteric. The diagnosis rates of the internal opening with digital examination and MRI were 48% and 84%, the rates of the primary tract were 76% and 100%, and the rates of the secondary extensions were 57.9% and 94.7% respectively. The differences in detection of internal opening, primary tract and secondary extensions between MRI and digital examination were significant (P<0.01).
  
  
  CONCLUSIONS
  MRI with the phased-array coil can correctly orient the internal opening and direction of the complex anal fistula, and find the relationship between anorectal sphincters and the complex fistula.
authors.affiliation: Department of Colorectal Surgery, The Affiliated Hospital, Nanjing University of Traditional Chinese Medicine, Nanjing, China.
authors.forename: Bo-Lin
authors.initials: BL
authors.lastname: Yang
authors.forename: Yun-Fei
authors.initials: YF
authors.lastname: Gu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhu
authors.forename: Wan-Jin
authors.initials: WJ
authors.lastname: Shao
authors.forename: Gui-Dong
authors.initials: GD
authors.lastname: Sun
authors.forename: Shu-Qing
authors.initials: SQ
authors.lastname: Ding
authors.forename: Hei-Ying
authors.initials: HY
authors.lastname: Jin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012003:Rectal Fistula / Q000175:diagnosis* / Q000473:pathology; D055815:Young Adult