title: Usefulness of magnetic resonance imaging for diagnosing deep anorectal abscesses.
abstract: OBJECTIVE
  We evaluated the usefulness of magnetic resonance imaging for the preoperative diagnosis of deep anorectal abscesses.
  
  
  METHODS
  Subjects were 21 patients with deep anorectal abscesses. Deep anorectal abscesses were classified into two types, ischiorectal and pelvirectal, according to their location. Patients were also classified into a single abscess group, which showed either an ischiorectal or pelvirectal abscess, and a double abscess group, which showed both ischiorectal and pelvirectal abscesses. The final diagnosis was made from surgical findings, and the types of deep anorectal abscesses determined by digital examination and magnetic resonance imaging were compared.
  
  
  RESULTS
  Sensitivity of ischiorectal abscesses (20 lesions) with digital examination and magnetic resonance imaging was 75 and 95 percent, respectively, and that of pelvirectal abscesses (10 lesions) with digital examination and magnetic resonance imaging was 60 and 70 percent, respectively. Sensitivity of the magnetic resonance imaging was significantly higher than that of digital examination in ischiorectal abscesses. Diagnostic accuracy of digital examination and magnetic resonance imaging were both 83 percent in the single abscess group (12 patients), whereas in the double abscess group (9 patients) it was 22 and 78 percent, respectively. The rate of accurate diagnosis of magnetic resonance imaging compared with digital examination in the double abscess group was significantly higher than that in the single abscess group.
  
  
  CONCLUSIONS
  Magnetic resonance imaging was useful for diagnosing and differentiating ischiorectal and pelvirectal abscesses.
authors.affiliation: Coloproctology Center, Takano Hospital, Kumamoto, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Maruyama
authors.forename: T
authors.initials: T
authors.lastname: Noguchi
authors.forename: M
authors.initials: M
authors.lastname: Takano
authors.forename: K
authors.initials: K
authors.lastname: Takagi
authors.forename: N
authors.initials: N
authors.lastname: Morita
authors.forename: R
authors.initials: R
authors.lastname: Kikuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Uchida
mesh_terms: D000038:Abscess / Q000175:diagnosis*; D000328:Adult; D001004:Anus Diseases / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010808:Physical Examination; D012002:Rectal Diseases / Q000175:diagnosis*; D012680:Sensitivity and Specificity