title: Hydrogen peroxide-enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging in evaluating perianal fistulas: agreement and patient preference.
abstract: OBJECTIVE
  To determine agreement between hydrogen peroxide-enhanced three-dimensional endoanal ultrasonography (3D HPUS) and endoanal magnetic resonance imaging (MRI) in preoperative assessment of perianal fistulas, and to assess patient preference with regard to these techniques.
  
  
  METHODS
  Forty patients (31 males, aged 21-70 years) with symptoms of a perianal fistula and a visible external opening underwent preoperative 3D HPUS and endoanal MRI. The results were assessed separately by experienced observers. Fistulas were described according to the following characteristics: classification of the primary fistula tract according to Parks, location of the internal opening, presence of secondary tracts and fluid collections. Patients were asked to score the amount of discomfort experienced during both procedures and express their preference for either method.
  
  
  RESULTS
  The median time interval between 3D HPUS and endoanal MRI was 14 days (range, 0-91 days). The methods agreed in 88% (35/40, kappa = 0.45) for the primary fistula tract, in 90% (36/40, kappa = 0.83) for the location of the internal opening, in 78% (31/40, kappa = 0.62) for secondary tracts, and in 88% (35/40, kappa = 0.63) for fluid collections. Both methods were associated with similar discomfort, and there was no patient preference for one procedure over the other.
  
  
  CONCLUSIONS
  3D HPUS and endoanal MRI are equally adequate for the evaluation of perianal fistulas. Both methods are associated with similar discomfort and patients have no preference for either procedure.
authors.affiliation: Department of Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, The Netherlands. r.west@erasmusmc.nl
authors.forename: Rachel L
authors.initials: RL
authors.lastname: West
authors.forename: Soendersing
authors.initials: S
authors.lastname: Dwarkasing
authors.forename: Richelle J F
authors.initials: RJ
authors.lastname: Felt-Bersma
authors.forename: W Ruud
authors.initials: WR
authors.lastname: Schouten
authors.forename: Wim C J
authors.initials: WC
authors.lastname: Hop
authors.forename: Shahid M
authors.initials: SM
authors.lastname: Hussain
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Kuipers
mesh_terms: D000328:Adult; D000368:Aged; D001004:Anus Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011300:Preoperative Care / Q000379:methods; D012003:Rectal Fistula / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies
chemical_list: D006861:Hydrogen Peroxide