Effects of head position on cochlear implant MRI artifacts at 3 T in vivo

Patients after An-resection need to be followed-up postoperatively over years by an MRI. MRI scanning in patient with CI is associated with side effects. Scan- related artifacts are known prolems. Since cochlear implantation can be an important part of the audiological rehabilitation of acoustic neuroma patients MRI scanning is of high interest. New studies showed that the right position of the CI receiver allows an postoperative artifact-free examination of the internal auditory canal (IAC) and the cochlea. The aim of this study is to evaluate how the CI magnet related artifact depends on the head position of the patient within the 3T MRI scanner.

We performed an vivo measurement of MRI artifacts at 3 Tesla with a Cochlea Implant with bipolar diametrical magnet. The implant was positioned 7,0 cm and 120 ° from the nasion, external auditory canal to internal magnet. We use high-resolution TSE T2w 0,8 mm MRI sequence in axial and coronar overview and observed thress positions: 1) Range of motion, 2) chin to chest, 3) hyperextension of the cervial spine.

Comparing the different positions a complete assessment of the internal auditoy canal and the labyrinth was possible in all scans independent from the head position. The hyperextension of the cervical spine by a head back rotation allowed us to shift the artifact more caudal under the IAC. The chin-to-chest position shifts the artifact more into the direction of the cochlea.

The location of MRI artifacts in CI patients can be influenced by the position of the head. Even in cases of unfavourable magnet to external auditory canal distance or angle an MRI can be useful. In these cases a hyperextension of the cervical spine by back rotation of the head in the MRI scanner should be tried to allow a visualization of the IAC

Publication History

Publication Date:
23 April 2019 (online)