Purpose: Vascular tracking of angiographic image sequences is one of the most clinically important tasks in the diagnostic assessment and interventional guidance of cardiac disease due to providing dynamic structural information for precise motion analysis and 3D+t reconstruction. However, this task can be challenging to accomplish because of unsatisfactory angiography image quality and complex vascular structures. Thus, this study converted vascular tracking into branch matching and proposed a new greedy graph search-based method for it.Methods: Each vascular branch was separated from the vasculature and was tracked independently.Then, all branches were combined using topology optimization, thereby resulting in complete vasculature tracking. An intensity-based image registration method was applied to determine the tracking range, and the deformation field between two consecutive frames was calculated. The vascular branch was described using a vascular centerline extraction method with multi-probability fusion-based topology optimization. We introduced an undirected acyclic graph establishment technique. A greedy search method was proposed to acquire all possible paths in the graph that might match the tracked vascular branch. The final tracking result was selected by branch matching using dynamic time warping with a DAISY descriptor.Results: For single branch dataset SBD, the proposed method was evaluated on 12 angiographic image sequences with 77 angiograms of contrast agent-filled vessels. The average precision, sensitivity and F1 score of the tracking result of all angiograms were 0.90, 0.89 and 0.89, respectively. The average F1 score of the tracking results of the first, middle and last frames in all sequences were 0.91, 0.91 and 0.86, respectively. In the vessel tree dataset VTD, the proposed method was validated on 9 angiographic image sequences with 58 angiograms of contrast agentfilled vessels. The average precision, sensitivity and F1 score of the tracking result of all angiograms were 0.89, 0.87 and 0.88, respectively. The average F1 score of the tracking results of the first, middle and last frames in all sequences were 0.94, 0.88 and 0.82, respectively. Compared with five other state-of-the-art methods, the proposed method accurately tracked the vasculature from angiographic image sequences and the results were insignificantly affected by the tracking span in both datasets.
Conclusions:The solution to the problem reflected both the spatial and textural information between successive frames. Thus, the proposed method is robust and highly effective in vascular tracking of angiographic image sequences and the approach provided a universal solution to address the problem of filamentary structure tracking.