Coregistration of Preoperative Computed Tomography and Intraoperative Three-Dimensional Rotational X-Ray Images for Cochlear Implant Surgical Evaluation

Objective: A registration procedure of intraoperative three-dimensional rotational x-ray (3DRX) imaging and preoperative computed tomography (CT) imaging so that intraoperative CT quality imaging is available during cochlear implant surgery, providing detailed information concerning electrode position in the cochlea and its relation to surrounding bony structures. Study Design: Retrospective case series Setting: Tertiary referral center Data: The imaging of five patients who had undergone cochlear implant surgery is used to develop a semiautomatic registration procedure to integrate intraoperative 3DRX and preoperative CT. The method is implemented in advanced medical imaging software to compute the transformations. The electrode is segmented from the registered 3DRX images using a semiautomated approach. The segmented electrode is superimposed onto the CT data. The methods are quantitatively validated based on expert-labeled anatomical landmarks. These landmarks are identified in the CT and 3DRX images by an expert. Main Outcome Measure: Mean error of the registration procedure for five anatomical landmarks in millimeters. Results: Quantitative analysis showed a mean error of between 0.5 and 1 mm for all anatomical landmarks, suggesting that the results are trustworthy. Conclusion: We developed a reliable procedure for the registration of intraoperative 3DRX imaging and preoperative CT imaging for cochlear implant surgery. This registration procedure provides the ENT surgeon intraoperative high-quality CT imaging during cochlear implant surgery.