The Image Fusion Technique for Cochlear Implant Imaging: A Study of its Application for Different Electrode Arrays.

Abstract

To investigate the benefits of the image fusion technique for precise postoperative assessment of intracochlear placement with six different electrode arrays. Consecutive retrospective case study. Tertiary referral center. Analyses of imaging data of 30 patients implanted with six different electrode arrays. Electrode reconstructions obtained from postoperative cone-beam computed tomography (CBCT) were overlaid onto preoperative magnetic resonance imaging (MRI) and/or high-resolution computed tomography (HRCT) registrations to create artefact-free images. Each electrode's intracochlear position was analyzed with the image fusion reconstructions and compared with the results obtained by CBCT alone. The electrode location was classified according to its position in relation to the basal membrane at four different insertion angles. In 40 out of 151 measurements (26.5%), the location grading obtained by CBCT alone changed after the assessment with the image fusion reconstructions. A significant association was found between deep insertions (over 360 degrees) and the effectiveness of image fusion (p = 0.019). The difference between the impact of the fusion technique for the basal turn versus the apical part was highly significant (p = 0.001). There was no significant difference between the effectiveness of the image fusion and the different electrodes. By utilizing an image fusion technique, a more accurate assessment of electrode placement could be achieved for all types of electrodes. Image fusion was especially beneficial for insertions beyond 360 degrees.