Monte Carlo Tree Search for 3D2D Registration of Vessel Graphs 3D2D registration techniques can compensate for the deficiencies of Xray angiographybased navigation in vascular interventional surgery, such as the lack of depth information and excessive use of contrast agents. In this study, we propose a novel Monte Carlo tree searchbased 3D2D vessel graph registration method. The registration problem is transferred to a tree search problem according to the topology of vessel centerlines. Then, the Monte Carlo tree search method is applied to find the optimal vessel matching associated with highest registration score. Experiments on uninitialized vessel data demonstrate that the proposed method can achieve the highest accuracy among four stateoftheart methods. An average accuracy of 1.91 mm on clinical coronary artery data is obtained. For the independence of initial pose and robustness to noise, the proposed method can align 3D and 2D vessels without prior initialization in vascular interventional surgery.

MultiView Global 2D3D Registration Based on Branch and Bound Algorithm In imageguided minimally invasive surgery, the clinician relies on image guidance to observe, plan and navigate. In order to show invisible vessels or planning annotations in live Xray images, or update the live information for planning, the correspondence establishment between 2D Xray images and preoperatively acquired 3D CT images is a fundamental step. Accurate image alignment is needed and can be provided by 2D3D registration by bringing a preoperative 3D image and intraoperative 2D image into the same coordinate. In this work, we propose a novel method to register 3D volume with multiview 2D images. Based on the Branch and Bound algorithm, the method can globally search the optimal pose and find the correspondence. Compared to the singleview setting, the multiview 2D image information can speed up the searching. Extensive experiments are conducted to evaluate the effectiveness of the proposed method. The accuracy is improved and the iteration numbers are reduced with the introduction of new views.