title: MRI without magnet removal in neurofibromatosis type 2 patients with cochlear and auditory brainstem implants.
abstract: OBJECTIVE
  To assess the impact on image quality of MRI without magnet removal in cochlear implant (CI) and auditory brainstem implant (ABI) users with neurofibromatosis type 2 (NF2).
  
  
  METHODS
  Prospective cohort.
  
  
  METHODS
  Tertiary center for cochlear and auditory brainstem implantation.
  
  
  METHODS
  Thirteen patients (10 ABI, 3CI) with NF2 underwent a total of 76 MRI scans.
  
  
  METHODS
  MRI without magnet removal.
  
  
  METHODS
  Ability to visualize the ipsilateral and contralateral cerebellopontine angles (CPAs) and internal auditory meati (IAM) with head MRI.
  
  
  RESULTS
  Of the 76 scans, 40 were of the head, 28 of the spine and 8 of other regions. Scanning was performed with a tight head bandage and plastic card. There were no cases of altered implant function or demagnetization of the device magnet.A grading system was used to assess the view of the ipsilateral IAM-CPA. In 85% of head scans, the view was unimpaired (Grade 0). In 13%, there was distortion (Grade 1). In 2% (1 case), the view was entirely obscured by artifact (Grade 2). Views of the contralateral CPA and IAM were unimpaired in all cases. The best 3 sequences for the depiction of the ipsilateral IAM-CPA (percent graded as 0) were as follows: axial 3D inversion recovery prepared fast spoiled gradient echo (100%), 2 mm coronal T1W of the IAM-CPA (88.9%), and 2 mm axial T1W of the IAM-CPA (76.9%).
  
  
  CONCLUSIONS
  MRI scanning without magnet removal is safe and well tolerated in NF2 patients with auditory implants. With appropriate MRI sequences, the image quality is not significantly impaired.
authors.affiliation: *Otology and Skull Base Unit, †Cambridge Hearing Implant Program, ‡Department of Radiology, and §Department of Neurosurgery, Cambridge University Hospital, Cambridge, U.K.
authors.forename: Joanna
authors.initials: J
authors.lastname: Walton
authors.forename: Neil P
authors.initials: NP
authors.lastname: Donnelly
authors.forename: Yu Chuen
authors.initials: YC
authors.lastname: Tam
authors.forename: Ilse
authors.initials: I
authors.lastname: Joubert
authors.forename: Juliette
authors.initials: J
authors.lastname: Durie-Gair
authors.forename: Cay
authors.initials: C
authors.lastname: Jackson
authors.forename: Richard A
authors.initials: RA
authors.lastname: Mannion
authors.forename: James R
authors.initials: JR
authors.lastname: Tysome
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Axon
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Scoffings
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D038262:Auditory Brain Stem Implants; D001921:Brain / Q000473:pathology*; D002528:Cerebellar Neoplasms / Q000473:pathology; D002530:Cerebellopontine Angle / Q000473:pathology; D003054:Cochlear Implants; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059346:Magnets; D008297:Male; D008875:Middle Aged; D016518:Neurofibromatosis 2 / Q000473:pathology*; D009464:Neuroma, Acoustic / Q000473:pathology; D011446:Prospective Studies; D055815:Young Adult