Localization of cochlear implant: electrodes in radiographs

Multielectrode cochlear implantation is the most effective treatment for pr ofound sensorineural hearing loss. In vivo three-dimensional 3-D localizati on of cochlear implant electrodes is important for modeling of the electric al field in the cochlea, design of electrode arrays, and may improve speech processor programming for better speech recognition. The prerequisite for 3-D localization of the electrodes is their 2-D localization in x-ray radio graphs. In this paper, we develop a practical method to localize the electr odes with high efficiency, accuracy, and reproducibility. In this method, a priori knowledge of the electrodes and their approximate positions are uti lized, an intelligent thresholding and segmentation mechanism is embedded, and the electrode center is computed as the weighted geometric center of se gmented electrode pixels. Experiments with physical phantoms and human data demonstrate the feasibility and utility of this method. The PC-based progr am developed for this project is disseminated on the Web, (C) 2000 American Association of Physicists in Medicine.