J Neurol Surg B Skull Base 2012; 73 - A285
DOI: 10.1055/s-0032-1314200

MRI without Magnet Removal in NF2 Patients with Cochlear and Auditory Brainstem Implants

N. Donnelly 1(presenter), C. Jackson 1, Y. C. Tam 1, I. Joubert 1, J. Tysome 1, P. Patel 1, P. Axon 1, R. Mannion 1, J. Durie-Gair 1, R. Macfarlane 1, D. Scoffings 1
  • 1Cambridge, UK

Objective: To assess the impact on image quality of MRI without magnet removal in cochlear implant (CI) and auditory brainstem implant (ABI) users with NF2.

Study Design: Prospective cohort.

Setting: Tertiary center for cochlear and auditory brainstem implantation.

Patients: Twelve patients (10 ABI, 2 CI) with NF2 underwent a total of 77 MRI scans.

Outcome Measure: Ability to visualize the ipsilateral internal auditory meatus.

Results: Of the 77 scans, 43 were of the head, 27 of the spine, and 7 of other regions. Scanning MRI was initially performed with a tight head bandage. After an early magnet displacement, the technique was adjusted to include a credit card sized piece of plastic over the long axis of the receiver stimulator. Two scans were abandoned due to pain (1 head, 1 spine) and were completed after injection of local anesthetic. There were no cases of altered implant function.

In 67% of head scans, the view of the ipsilateral IAM was unimpaired. In the remaining 33%, the ipsilateral IAM was partially obscured but did not preclude the ability to view a vestibular schwannoma or assess for recurrence. There were no cases where it was not possible to view the ipsilateral IAM, and the contralateral IAM was unimpaired in all cases.

Conclusion: MRI scanning without magnet removal is safe and well tolerated in NF2 patients with auditory implants. Image quality is not significantly impaired.