title: The use of cone-beam computed tomography to determine cochlear implant electrode position in human temporal bones.
abstract: OBJECTIVE
  To assess the utility of cone-beam computed tomography (CBCT) imaging in the estimation of cochlear implant (CI) electrode position in implanted temporal bones.
  
  
  METHODS
  Eight fresh frozen temporal bones were mounted and oriented as for standard surgery and were implanted with Cochlear Slim-Straight (SS) or Contour Advance electrode arrays by 2 CI surgeons. The bones were then imaged using an Accuitomo F170 CBCT scanner (isometric 250 μm voxel size) and were then processed for histologic sectioning (500 μm sections).
  
  
  METHODS
  The CBCT images and the histologic micrographs (providing the "gold standard") were examined independently by several observers who assessed the scalar position (tympani or vestibuli) of each electrode in each temporal bone specimen.
  
  
  RESULTS
  Examination of the histologic micrographs confirmed that all electrodes were positioned within the scala tympani in all 8 bones. Similar judgments were made by the observers rating the CBCT images, except that one of the 2 observers estimated some of the apical electrodes to be located in the scala vestibuli in two of the bones implanted with the SS electrode.
  
  
  CONCLUSIONS
  Cone-beam CT imaging is able to provide a good indication of the scalar position of implanted electrodes, although estimation may be slightly less reliable for apical electrodes and for straight electrode designs. Additional advantages of using CBCT for this purpose are shorter acquisition time and reduction of radiation dose as compared with conventional CT.
authors.affiliation: *University College London Ear Institute, Royal National Throat, Nose and Ear Hospital; †St George's Hospital, London, United Kingdom; ‡St Vincent's Hospital, Sydney, Australia; §Cochlear Europe Ltd, London, United Kingdom; ∥Cochlear Ltd, Sydney, Australia; and ¶Manchester Ear Nose and Throat Clinic, Manchester, United Kingdom.
authors.forename: Shakeel R
authors.initials: SR
authors.lastname: Saeed
authors.forename: David
authors.initials: D
authors.lastname: Selvadurai
authors.forename: Tim
authors.initials: T
authors.lastname: Beale
authors.forename: Nigel
authors.initials: N
authors.lastname: Biggs
authors.forename: Brendan
authors.initials: B
authors.lastname: Murray
authors.forename: Peter
authors.initials: P
authors.lastname: Gibson
authors.forename: Frank
authors.initials: F
authors.lastname: Risi
authors.forename: Paul
authors.initials: P
authors.lastname: Boyd
mesh_terms: D002102:Cadaver; D003051:Cochlea / Q000601:surgery; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D013701:Temporal Bone / Q000000981:diagnostic imaging* / Q000601:surgery*