Toward Interactive User Guiding Vessel Axis Extraction from Gray-scale Angiograms: An Optimization Framework

We propose a novel trace-based method to extract vessel axes from gray-scale angiograms without preliminary segmentations. Our method traces the axes on an optimization framework with the bounded spherical projection images and the sum of squared difference metric. It does not take alternate steps to search the next axial point and its tangent as in other trace-based algorithms, instead the novel method finds the solution simultaneously. This helps avoid U-turns of the trace and large spatial discontinuity of the axial points. Another advantage of the method is that it enables interactive user guidance to produce continuous tracing through regions that contain furcations, disease portions, kissing vessels (vessels in close proximity to each other) and thin vessels, which pose difficulties for the other algorithms and make re-initialization inevitable as illustrated on synthetic and clinical data sets.