Cone Beam Imaging of Cochlear Implants

Abstract Objectives to assess the role of Cone Beam CT (CBCT) in the postoperative cochlear implant (CI) imaging in determining details about the electrode position, insertion depth, angle and other fine anatomical details. Methods This retrospective study included 32 patients (34 ears) with post-CI CBCT imaging. All images were anonymized and reviewed by two experienced head and neck radiologists in consensus for the measurements of the implant insertion depth, facial canal (vertical part) diameter, wall thickness and distance between it and the electrode cable, then assessment of the quality of visualization of fine structures as the facial nerve canal, chorda tympani, separate electrode contacts and scalar position of electrodes were done using 4-point scale. Results The insertion angles for the electrodes were measured in all the ears with a mean ± SD = 430.24 ± 121.43, the facial canal diameters were measured in 97.1% (33 ears) with a mean ± SD = 1.54 ± 0.33, the facial wall thickness was measured in 79.4% (27 ears) with a mean ± SD = 0.62 ± 0.32, the facial canalelectrode cable distances were measured in 97.1% (33 ears) with a mean ± SD = 1.64 ± 0.50 and the chorda tympani was visualized in 88.2% (30 ears). Perfect visualization of the scalar position of electrodes were encountered in 76.5% (26 ears), separate electrode contacts in 20.6% (7 ears), facial canal in 35.3% (12 ears), facial canal wall in 26.5% (9 ears), and chorda tympani in 41.2% (14 ears). Conclusion CBCT is a valuable tool in the postoperative assessment of cochlear implants