title: Three-dimensional endoanal ultrasonographic assessment of an anal fistula with and without H(2)O(2) enhancement.
abstract: OBJECTIVE
  To evaluate the effectiveness of three-dimensional endoanal ultrasound (3D-EAUS) in the assessment of anal fistulae with and without H(2)O(2) enhancement.
  
  
  METHODS
  Sixty-one patients (37 males, aged 17-74 years) with anal fistulae, which were not simple low types, were evaluated by physical examination and 3D-EAUS with and without enhancement. Fistula classification was determined with each modality and compared to operative findings as the reference standard.
  
  
  RESULTS
  The accuracy of 3D-EAUS was significantly higher than that of physical examination in detecting the primary tract (84.4% vs 68.7%, P = 0.037) and secondary extension (81.8% vs 62.1%, P = 0.01) and localizing the internal opening (84.2% vs 59.7%, P = 0.004). A contrast study with H(2)O(2) detected several more fistula components including two primary suprasphincteric fistula tracks and one supralevator secondary extension, which were not detected on non-contrast study. However, there was no significant difference in accuracy between 3D-EAUS and H(2)O(2)-enhanced 3D-EAUS with respect to classification of the primary tract (84.4% vs 89.1%, P = 0.435) or secondary extension (81.8% vs 86.4%, P = 0.435) or localization of the internal opening (84.2% vs 89.5%, P = 0.406).
  
  
  CONCLUSIONS
  3D-EAUS was highly reliable in the diagnosis of an anal fistula. H(2)O(2) enhancement was helpful at times and selective use in difficult cases may be economical and reliable.
authors.affiliation: Department of Surgery, Dongguk University Ilsan Hospital, Ilsandong-Gu, Goyang-Si, Gyeonggi-Do, South Korea.
authors.forename: Yung
authors.initials: Y
authors.lastname: Kim
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000494:pharmacology; D019160:Endosonography / Q000379:methods*; D005260:Female; D005762:Gastroenterology / Q000379:methods; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007089:Image Enhancement; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D012003:Rectal Fistula / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D006861:Hydrogen Peroxide