Abstract：Objective: Postoperative imaging of cochlear implants needs to provide detailed information on localization, insertion depth and visualization of the electrode array. We evaluated these information with 256-slice CT and several processing techniques. Materials and Methods: The clinical histories and CT studies of 15 children with cochlear implants were retrospectively analyzed. Images in this thesis were acquired from 256-slice Brillance iCT(Philips Healthcare) scanner with helical mode. Then we reconstructed two image sequences of the interesting temporal with a small FOV(9 cm) using a high resolution reconstruction algorithm and low resolution reconstruction algorithm respectively. Multi-planar reformations perpendicular and parallel to the modiolar axis were made with contiguous 0.2 mm sections. The volume rendering was made with the image sequence of low resolution reconstruction algorithm. On oblique coronal and oblique saggital reformation images, we evaluate the information of cochlear implants on the precise localization of the implant and its individual contacts as well as the visibility of electrode array. Additionally the number of the electrode array was counted and compared with the surgical recording. On a multi-planar reformation perpendicular to the modiolus axial image, we evaluate the visibility of electrode array. The image was evaluated by 2 head and neck radiologists using a 2-point scale. Results: The interobserver agreement for the visibility of electrodes was very high, t=2.092, P=0.055>0.05. Axial CT and multi-planar reformation images can provide the inserted electrode number and had no significant difference between surgical recording, t=1.468, P=0.164>0.05. Conclusion: Postoperative CT of cochlear implants should provide information on the precise localization of the implant and its individual electrode. And on the multi-planar reformation perpendicular and parallel to the modiolus axis, the number of the implanted electrodes can be evaluated. The volume rendering technique can give a outlook of totality of the implants.
2014, Vol. 25 
