Co-registration of cone beam CT and preoperative MRI for improved accuracy of electrode localization following cochlear implantation

Abstract

Objectives: To investigate the clinical usefulness and practicality of co-registration of Cone Beam CT (CBCT) with preoperative Magnetic Resonance Imaging (MRI) for intracochlear localization of electrodes after cochlear implantation.

Methods: Images of 20 adult patients who underwent CBCT after implantation were co-registered with preoperative MRI scans. Time taken for co-registration was recorded. The images were analysed by clinicians of varying levels of expertise to determine electrode position and ease of interpretation.

Results: After a short learning curve, the average co-registration time was 10.78 minutes (StdDev 2.37). All clinicians found the co-registered images easier to interpret than CBCT alone. The mean concordance of CBCT vs. co-registered image analysis between consultant otologists was 60% (17-100%) and 86% (60-100%), respectively. The sensitivity and specificity for CBCT to identify Scala Vestibuli insertion or translocation was 100 and 75%, respectively. The negative predictive value was 100%.

Discussion: CBCT should be performed following adult cochlear implantation for audit and quality control of surgical technique. If SV insertion or translocation is suspected, co-registration with preoperative MRI should be performed to enable easier analysis. There will be a learning curve for this process in terms of both the co-registration and the interpretation of images by clinicians.

Keywords:

• Preoperative MRI
• Co-registration
• Cone beam CT
• Electrode localization
• Cochlear implantation
• Translocation
• Scala tympani
• Scala vestibuli

Disclaimer statements

Contributors None

Funding None

Conflict of interest None

Ethics approval Ethics approval for this research was granted by the Royal Victorian Eye and Ear Hospital Human Research Ethics Committee (HREC) [Approval number: 17/1347HS].

ORCID

A. S. Dragovic http://orcid.org/0000-0002-6436-1628

A. K. Stringer http://orcid.org/0000-0002-6490-3327

S. J. O’Leary http://orcid.org/0000-0001-6926-2103