Improved cochlear implant electrode localization using coregistration of pre- and postoperative CT

J Neuroimaging. 2023 May-Jun;33(3):387-392. doi: 10.1111/jon.13094. Epub 2023 Feb 22.

Abstract

Background and purpose: Artifact from cochlear implant electrodes degrades image resolution on CT. Here, we describe the use of coregistered pre- and postoperative CT images to reduce metallic artifact from the electrodes to assess its position more accurately within the cochlear lumen.

Methods: Pre- and postoperative CTs were reviewed after coregistration/overlay of both exams. Images were evaluated by two neuroradiologists for scalar location of electrodes tip (± scalar translocation), tip fold over, and angular depth of insertion.

Results: Thirty-four patients were included in the final cohort. Transscalar migration was present in three (8.8%) cases (one case demonstrated tip fold over), with initial disagreement regarding transscalar migration in 1 out of 34 patients (2.9%). Agreement regarding depth of insertion was present in 31 (91.1%) cases. Five-point Likert scales were used to compare the ability to resolve the proximity of electrodes to the lateral/outer cochlear wall without and with overlay, which is a qualitative measure of artifact from the array. Likert scores showed definitive benefit of metal artifact reduction using overlayed images with an average score of 4.34.

Conclusion: This study demonstrates a novel technique of using fused coregistration of pre- and postoperative CTs for the purpose of artifact reduction/electrode localization. It is anticipated that this technique will permit more accurate localization of the electrodes for improvement in surgical technique and electrode array design.

Keywords: cochlear implants; computed tomography; coregistration; hearing loss.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cochlea / surgery
  • Cochlear Implantation* / methods
  • Cochlear Implants*
  • Electrodes, Implanted
  • Humans
  • Tomography, X-Ray Computed / methods