Development and Use of Imaging to Understand Cochlear Morphology and Assess Intracochlear Trauma by CI

Background: In cochlear implantation preservation of intracochlear structures during surgery has become important. It is key to develop methods which allows CI developers to better tailor the development of the CI to those needs and help surgeons preserve the cochlea.

Objective: The objective was to develop imaging methods in order to visualize intracochlear structures and define the intracochlear morphology and to assess trauma and location of the CI electrode array after implantation.

Methods: Human cadaver temporal bones were scanned using micro-CT with different scanners and parameter settings both for pre-op condition without electrode array as for post op condition with electrode array. The temporal bones were prepared using different methodologies. Mimics and Matlab have been used to analyze the cochlea morphology.

Results: The cochlear fluid had to be suctioned out to obtain better image contrast. Scanning parameters for the micro-CT machine have been developed for pre- and post insertion, varying input voltage, current, and different filters. Morphological analysis showed large variation between cochleae with difference in width, length and vertical trajectory. A formula has been created which allows assessing the length of the cochlear duct on clinical scanners.

Conclusion: Micro-CT scanning parameters have been developed to generate a library of cochleae to assess cochlear morphology and to identify the electrode location and trauma post operatively. The cochleae showed large variability, and a formula has been created which allows to asses the length of the cochlea.