title: CT detection of facial canal dehiscence and semicircular canal fistula: comparison with surgical findings.
abstract: OBJECTIVE
  The purpose of this study was to determine the accuracy of high resolution CT (HRCT) in the detection of facial canal dehiscence and semicircular canal fistula, the preoperative evaluation of both of which is clinically very important for ear surgery.
  
  
  METHODS
  We retrospectively reviewed the HRCT findings in 61 patients who underwent mastoidectomy at Yamagata University between 1989 and 1993. The HRCT images were obtained in the axial and semicoronal planes using 1 mm slice thickness and 1 mm intersection gap.
  
  
  RESULTS
  In 46 (75%) of the 61 patients, the HRCT image-based assessment of the facial canal dehiscence coincided with the surgical findings. The data for the facial canal revealed sensitivity of 66% and specificity of 84%. For semicircular canal fistula, in 59 (97%) of the 61 patients, the HRCT image-based assessment and the surgical findings coincided. The image-based assessment in the remaining two patients, who both had massive cholesteatoma, was false-positive.
  
  
  CONCLUSIONS
  HRCT is useful in the diagnosis of facial canal dehiscence and labyrinthine fistula, but its limitations should also be recognized.
authors.affiliation: Department of Otorhinolaryngology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fuse
authors.forename: Y
authors.initials: Y
authors.lastname: Tada
authors.forename: M
authors.initials: M
authors.lastname: Aoyagi
authors.forename: Y
authors.initials: Y
authors.lastname: Sugai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005402:Fistula / Q000175:diagnosis*; D006801:Humans; D007759:Labyrinth Diseases / Q000175:diagnosis*; D008416:Mastoid / Q000601:surgery; D008875:Middle Aged; D010033:Otitis Media / Q000601:surgery; D012189:Retrospective Studies; D012665:Semicircular Canals; D012680:Sensitivity and Specificity; D013701:Temporal Bone / Q000033:anatomy & histology*; D014057:Tomography, X-Ray Computed