Real-Time 3D Instrument Tip Tracking Using 2D X-Ray Fluoroscopy With Vessel Deformation Correction Under Free Breathing

Objective: Accurate localization of the instrument tip within the hepatic vein is crucial for the success of transjugular intrahepatic portosystemic shunt (TIPS) procedures. Real-time tracking of the instrument tip in X-ray images is greatly influenced by vessel deformation due to patient's pose variation, respiratory motion, and puncture manipulation, frequently resulting in failed punctures. Method: We propose a novel framework called deformable instrument tip tracking (DITT) to obtain the real-time tip positioning within the 3D deformable vasculature. First, we introduce a pose alignment module to improve the rigid matching between the preoperative vessel centerline and the intraoperative instrument centerline, in which the accurate matching of 3D/2D centerline features is implemented with an adaptive point sampling strategy. Second, a respiration compensation module using monoplane X-ray image sequences is constructed and provides the motion prior to predict intraoperative liver movement. Third, a deformation correction module is proposed to rectify the vessel deformation during procedures, in which a manifold regularization and the maximum likelihood-based acceleration are introduced to obtain the accurate and fast deformation learning. Results: Experimental results on simulated and clinical datasets show an average tracking error of 1.59 $\pm$ 0.57 mm and 1.67 $\pm$ 0.54 mm, respectively. Conclusion: Our framework can track the tip in 3D vessel and dynamically overlap the branch roadmapping onto X-ray images to provide real-time guidance. Significance: Accurate and fast (43ms per frame) tip tracking with the proposed framework possesses a good potential for improving the outcomes of TIPS treatment and minimizes the usage of contrast agent.