title: The limitations of computed tomography in adult cochlear implant evaluation.
abstract: OBJECTIVE
  To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) during adult cochlear implant evaluation.
  
  
  METHODS
  Two adult patients are discussed in whom MRI studies diagnosed bilateral vestibular schwannomas during cochlear implant candidacy evaluation.
  
  
  METHODS
  Temporal bone CT and MRI.
  
  
  METHODS
  Diagnosis of NF2.
  
  
  RESULTS
  Two adult patients, ages 67 and 68 years, were evaluated for cochlear implant candidacy. Both patients experienced slowly progressive, bilateral hearing loss without complaints of vertigo, and neither patient had a family history of hearing loss or neurogenic tumors. Both patients had near-symmetric pure tone thresholds on audiometric testing. An MRI and a CT scan were performed on both patients, and bilateral vestibular schwannomas were identified on MRI.
  
  
  CONCLUSIONS
  Though MRI is not routinely utilized in adult cochlear implant evaluation, it may be of greater clinical value than CT in the setting of adult-onset hearing loss. MRI allows for sensitive evaluation of cochlear patency and architecture, and cochlear nerve status. As demonstrated in the two index cases, MRI also provides the added benefit of evaluating for causes of retrocochlear hearing loss. These two patients would have likely experienced a significant delay in diagnosis of NF2 without preoperative MRI, particularly given the limitations of scanning following CI magnet placement.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Alex D
authors.initials: AD
authors.lastname: Sweeney
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Carlson
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rivas
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Marc L
authors.initials: ML
authors.lastname: Bennett
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Haynes
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA. Electronic address: george.wanna@vanderbilt.edu.
authors.forename: George B
authors.initials: GB
authors.lastname: Wanna
mesh_terms: D000368:Aged; D003054:Cochlear Implants; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009464:Neuroma, Acoustic / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed; D014722:Vestibule, Labyrinth