Disclosed is a method and an apparatus for quantifying vascular fluid motions from digital subtraction angiography (DSA) images, comprising: calculating an optical flow field between two temporal consecutive DSA images； and estimating a displacement of blood or tissue between the two temporal consecutive DSA images from the calculated optical flow field, wherein the optical flow field is calculated by solving a minimization problem of a CLG energy function, wherein the CLG energy function combines the temporally extended variant of Horn-Schunck approach with Lucas-Kanade approach non-linearly in spatiotemporal approach. The present disclosure provides a new optical flow solution significantly reducing the computation cost with a high robustness for quantifying vascular fluid motions from DSA.
