Evaluation of the implanted cochlear implant electrode by CT scanning with three-dimensional reconstruction.

Conclusions: Computed tomography (CT) scan with three-dimensional (3D) reconstruction of the inner ear provides a more accurate image of the relationship of the electrode within the cochlear canal, with direct demonstration of electrode insertion depth in the cochlea in comparison with X-ray plain film.

Objective: This study was designed to evaluate the value of spiral CT scans with 3D reconstruction in determining the insertion site and depth of implanted cochlear implant electrodes.

Methods: A total of 172 cochlear implant recipients were involved in this study. The implanted electrodes of all patients were examined by X-ray plain film, and 157 cochlear recipients were examined by spiral CT scans with axial 1 mm image slices. The data from the CT scans were transferred to a workstation for 3D reconstruction (direct volume rendering) of the inner ear. The pseudocolor technique was used to display the electrode.

Results: The insertion depth of the electrode could be evaluated indirectly by the X-ray plain film. In contrast, the stereoscopic images from a CT scan with 3D reconstruction of the inner ear demonstrated the shape, position, and insertion depth of the electrode more accurately.