title: [Magnetic resonance imaging study of perianal abscess].
abstract: OBJECTIVE
  To investigate magnetic resonance imaging(MRI) manifestations of perianal abscess and to evaluate MRI diagnosis for perianal abscess.
  
  
  METHODS
  Fifty cases of perianal abscess between July 2007 and March 2009 were included in this study. MRI was performed using T1 weighted sequence in axial plane, T2 weighted sequence with fat saturation in axial, coronal and/or sagittal plane, and T1 weighted enhanced sequence with fat saturation in axial, coronal and/or sagittal plane. The location, size, shape, signal characteristics, and enhancement patterns of perianal abscess were analyzed.
  
  
  RESULTS
  Fifty cases with 51 perianal abscesses were identified. The abscess appeared slight hypo- or isointense signal on T1 weighted imaging, obviously hyperintense signal at cavity and isointense signal at wall on T2 weighted with fat saturation imaging, and marked enhancement at wall. The largest diameters ranged between 0.5 cm and 9.0 cm (mean 3.4±1.7 cm ) in abscess, between 0.2 cm and 8.0 cm(mean 2.7±1.7 cm) in cavity. The abscess was round, oblong and crescent in 23, 18 and 7 cases respectively, and was unilocular in 41 cases and multilocular in 10 cases. The abscess located between levator ani and intersphincteric groove in 23 cases, under intersphincteric groove in 3 cases, across levator ani and intersphincteric groove in one case, on levator ani in 7 cases, on intersphincteric groove in 16 cases and above levator ani in one case.
  
  
  CONCLUSIONS
  MRI is a noninvasive, convenient and highly accurate procedure for diagnosing perianal abscess, which can demonstrate the anatomical relationship between abscess and anal canal.
authors: Department of Radiology, Fudan University, Shanghai 200540, China.
authors: Xiang
authors: X
authors: Li
authors: Jin-wei
authors: JW
authors: Qiang
authors: Cheng
authors: C
authors: He
authors: Xue-sheng
authors: XS
authors: Ji
authors: Biao
authors: B
authors: Zhang
mesh_terms: D000038:Abscess / Q000175:diagnosis / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001004:Anus Diseases / Q000175:diagnosis / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult