Cochlear implants: three-dimensional localization by means of coregistration of CT and conventional radiographs.

With use of radiopaque implanted objects as internal fiducial markers, the authors developed and evaluated a technique for coregistering computed tomographic (CT) and computed radiographic images to help determine three-dimensional location information for implant electrodes in the cochlea in phantoms and patients. Three-dimensional positional data from CT were assigned on a radiograph, which permitted identification of individual cochlear electrode locations that were not depicted at CT.