title: The accuracy of a postprocessing technique--volume render mode--in three-dimensional endoanal ultrasonography of anal abscesses and fistulas.
abstract: OBJECTIVE
  This study aimed to evaluate the accuracy of a 3-dimensional volume render mode endoanal ultrasonography in the assessment of anal abscesses and fistulas.
  
  
  METHODS
  Three-dimensional endoanal ultrasonography was performed preoperatively in 62 patients with clinical diagnoses of an anal abscess and/or an anal fistula. The accuracy of a volume render mode endoanal ultrasonography was evaluated blindly by 2 observers through a retrospective analysis of all the stored images of anal abscesses and fistulas. Differences in classification of the type of anal abscesses and in determination of the type and location of internal openings of anal fistulas were assessed.
  
  
  RESULTS
  In classification of the primary tract, the agreement between the volume render mode endoanal ultrasonography and surgery was much higher than that for the 3-dimensional endoanal ultrasonography (marginal homogeneity test P > .1, κ = 0.96, and marginal homogeneity test P = .0048, κ = 0.28, respectively). In localizing the internal openings and in classifying anal abscesses, the agreement for both methods with surgery was identical. The interobserver agreement showed complete agreement (100%) with regard to luminance and thickness parameters and very high accuracy for the opacity and filter parameters.
  
  
  CONCLUSIONS
  This study demonstrated that volume render mode endoanal ultrasonography is a useful adjunct method to the 3-dimensional endoanal ultrasonography, showing better classification results of the types of anal fistulas.
authors.affiliation: Department of Diagnostic Imaging, Medical University of Warsaw, Warsaw, Poland. sudolszopinska@gmail.com
authors.forename: Iwona
authors.initials: I
authors.lastname: Sudoł-Szopińska
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Kołodziejczak
authors.forename: Tomasz R
authors.initials: TR
authors.lastname: Szopiński
mesh_terms: D000038:Abscess / Q000000981:diagnostic imaging* / Q000601:surgery; D000328:Adult; D001003:Anal Canal / Q000000981:diagnostic imaging* / Q000601:surgery; D001004:Anus Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D012003:Rectal Fistula / Q000000981:diagnostic imaging* / Q000601:surgery; D012189:Retrospective Studies; D014463:Ultrasonography