Temporal bone MRI for the evaluation of cochlear implant electrode position

Introduction Computed tomography has been the state of the art for determining the electrode position after cochlear implant surgery. Despite having many benefits, it has its limitations. Recent developments regarding cochlear implant magnets (e.g. bipolar diametral magnet) and refined surgical technique (e.g. implant positioning) have made a significant impact on the relation between a cochlear implant and an MRI. MRI scanning has changed from a contraindication to a diagnostic tool. Physicians need to understand the electrode patterns to make affirmations, that could lead to better audiological outcomes.

Objective The aim of the study was to describe the characteristics of different electrode arrays in temporal bones by MRI, and to optimize/standardize the in vitro MRI-procedure.

Methods Temporal bone specimens were filled with fluid and inserted with different cochlear implant electrodes (Advance Bionics HFMS and MEDEL Flex 28). The temporal bones were placed in a gel-filled cool pack. Different T2 Drive coronal and axial multislice sequences were performed. A 3T MRI scanner was used.

Results Similar to the evaluation of CI electrodes by DVT or CT in temporal bones, the evaluation by MRI is possible. Different positions can be easily estimated in the temporal bone and help to visually understand the different patterns. Even the complex pattern in the coronal view can be followed.

Conclusion: This is the first study in temporal bones in which the position of the electrode inside the cochlea was evaluated by using 3 Tesla MRI scans. By optimizing the sequences, it was possible to demonstrate the different patterns of both of the electrodes.

Poster-PDF A-1311.pdf

Publication History

Article published online:
13 May 2021