Fast Registration of Intraoperative Ultrasound and Preoperative MR Images Based on Calibrations of 2D and 3D Ultrasound Probes

During the intraoperative-ultrasound-guided intervention, ultrasound (US) is often registered with other high-quality preoperative images like computed tomography (CT) or magnetic resonance (MR) to improve the navigation accuracy. However, real-time registration is difficult to achieve due to the difference of image modality and dimensionality. To solve this problem, we apply preoperative 3D US image collected with a 3D calibrated probe to simplify 2D US and 3D MR image registration into two easy-achieved steps: 2D-3D US intra-modal registration and 3D US 3D MR pre-operative registration. To achieve fast intraoperative 2D US and preoperative 3D US registration, we take advantage of effective 2D and 3D US probes' calibration results and get a near optimal registration transform. Then intraoperatively we just need to do an automatic local adjustment, which will make real-time registration become possible. To achieve effective calibrations, we design an improved calibration phantom and propose a warm-start iterative closest points (ICP) method.