Computed tomography of single-channel cochlear implants

Computed tomographic (CT) examinations were performed in seven patients after cochlear implant surgery. Preimplantation CT demonstrated the petrous anatomy well and revealed an abnormality in one case. Postimplantation CT adequately assessed electrode position in all cases. Malposition of the active electrode was identified in one patient. Electrode position was correlated with postimplantation audiometric testing. A "transpetrous" projection was used to image perpendicular to the active electrode within the basal turn of the cochlea. A potential pitfall was identified where the ground electrode tip appeared to be embedded in the carotid canal cortex due to partial-volume averaging. With further experience, the clinical utility of CT in cochlear implantation patients will be better defined.