Development of MRI resolution for the evaluation of electrode position in vivo

Background Recent developments regarding cochlear implant magnets (e.g., a bipolar diametral magnet) and refined surgical technique (e.g., implant positioning) have made a significant impact on the relation between a cochlear implant and MRI. MRI scanning has changed from a contraindication to a diagnostic tool. For the first time, a pain free in vivo evaluation of the fluid state of the cochlea, following the insertion of an electrode, has become possible via MRI scanning.

The aim of the study was to show the development of MRI resolution for evaluation of electrode position and to answer, if MRI can replace CT as a standard tool for postoperative quality control.

Methods: Over time different MRI sequences have been performed at 1.5 T and 3 T (T2 TSE, T2 3D Drive, T2 2 D Drive, MARS...) which allowed different resolutions, scanning times and artifacts sizes for the evaluation of IAC, cochlea and electrodes.

Results: MRI slice thickness developed from 1.5 mm to 0,8 mm down to 0,5 mm. Finally, a voxel size of 0,2 mm is possible. This resolution allows not only an estimation of electrode position in the axial but even in the coronal plane.

Conclusion: Cochlear implant electrode positional evaluation can be performed by MRI with a high resolution. Limitations persist in terms of estimation of insertional depth with lateral wall electrodes.

Poster-PDF A-1731.pdf

Publication History

Article published online:
13 May 2021