title: [Comparison of hydrogen peroxide-enhanced ultrasound with surgery in the diagnosis of perianal fistulas].
abstract: OBJECTIVE
  To evaluate the usefulness of hydrogen peroxide-enhanced ultrasound (H(2)O(2)) in the preoperative assessment of perianal fistulas and to compare these results with unenhanced ultrasound findings.
  
  
  METHODS
  All patients with surgically confirmed perianal fistula who underwent preoperative enhanced and unenhanced ultrasound were included. We compared enhanced and unenhanced ultrasound findings with surgical results (chi(2) and McNemar tests).
  
  
  RESULTS
  A total of 44 surgically treated patients were analysed. Hydrogen peroxide-enhanced ultrasound correctly identified primary fistula tracks in 34 patients (sensitivity of 77%), 100% of abscesses and the internal opening in 29 out of 37 identified with surgery (sensitivity of 78% and specificity of 70%). The use of hydrogen peroxide provided additional information to the ultrasound performed without the use of contrast enhancement in 32 of the 44 patients (73%). H(2)O(2) increased the number of fistula tracts correctly detected (77% vs 45%; p<0.003), particularly suprasphincteric fistulas, as well as internal openings (78% vs 22%; p<0.001) and secondary tracks (70% vs 0%). Additional detection of fistula tracks after H(2)O(2) injection was higher in patients with previous surgery (68% vs 35%; p<0.05).
  
  
  CONCLUSIONS
  Hydrogen peroxide-enhanced ultrasound shows good agreement compared with surgical findings in the assessment of perianal fistulas. H(2)O(2) improves conventional ultrasound results, increasing the detection of fistula tracks and internal openings, and also providing additional information, particularly in previously operated patients.
authors.affiliation: Servicio de Radiodiagnóstico, Hospital Universitario Doctor Peset, Valencia, Spain. bartumeus_pau@gva.es
authors.forename: Paula
authors.initials: P
authors.lastname: Bartumeus
authors.forename: Segundo Antonio
authors.initials: SA
authors.lastname: Gómez Abril
authors.forename: Tomás
authors.initials: T
authors.lastname: Ripollés
authors.forename: M Jesús
authors.initials: MJ
authors.lastname: Martínez Pérez
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cogollos
mesh_terms: D001004:Anus Diseases / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide; D007412:Intestinal Fistula / Q000000981:diagnostic imaging*; D008297:Male; D011300:Preoperative Care; D014463:Ultrasonography / Q000379:methods
chemical_list: D006861:Hydrogen Peroxide