title: Preoperative mapping of fistula-in-ano: a new three-dimensional MRI-based modelling technique.
abstract: OBJECTIVE
  We aimed to develop an intuitive, interactive, three-dimensional (3D) MRI modelling technique to produce a 3D image of fistula-in-ano.
  
  
  METHODS
  The 3D model was created from standard two-dimensional (2D) MRI sequences to produce an image that is anatomically correct. Individual muscle and soft-tissue layers were extracted from T1-weighted sequences and fistula pathology from short TI inversion recovery (STIR) sequences, to produce two separate volumes. These were then fused using postprocessing software (Vitrea Workstation version 6.3) to generate a 3D model.
  
  
  RESULTS
  The final 3D model was incorporated into a PDF file that has an integrated computer aided design (CAD) viewer, allowing the surgeon to rotate it in any direction during preoperative planning or whilst in theatre.
  
  
  CONCLUSIONS
  As an adjunct to 2D MRI images and the associated radiology report, this model communicates the fistula anatomy to the clinician more clearly and should be particularly useful in complex cases.
authors.affiliation: Wirral University Teaching Hospital NHS Foundation Trust, Arrowe Park Hospital, Wirral, Merseyside, UK.
authors.forename: N J
authors.initials: NJ
authors.lastname: Day
authors.forename: D
authors.initials: D
authors.lastname: Earnshaw
authors.forename: P
authors.initials: P
authors.lastname: Salazar-Ferrer
authors.forename: C J
authors.initials: CJ
authors.lastname: Walsh
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging; D057234:Preoperative Period; D012003:Rectal Fistula / Q000175:diagnosis* / Q000601:surgery*; D012984:Software
keywords: 3D; CAD; Fistula-in-ano; MRI; mapping; modelling