Methods and apparatuses for quantifying vascular fluid motions from DSA

An apparatus for quantifying vascular fluid motions from digital subtraction angiography (DSA) images, comprising:

• at least one processor;
• and
• a memory storing instructions, the instructions when executed by the at least one processor, cause the at least one processor to perform operations, the operations 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 combined local global (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,
• wherein the CLG energy function is established by:
• establishing an energy function by Horn-Schunck approach, which includes an energy term and a regularization term, wherein the energy term is determined by an estimated optical flow increment field and a gradient of an intensity field, and the intensity field is extended from a spatial field to a spatial-temporal field according to the two temporal consecutive DSA images;
• and
• transforming the gradient of the intensity field in a spatial-temporal vector space to a localized spatial-temporal derivative smoothing tensor by a convolution kernel, wherein the localized spatial-temporal derivative smoothing tensor is defined as Jρ(∇3I)=Kρ*(∇3I∇3IT), wherein ρ denotes for a localized constant flow assumed in Lucas-Kanade approach, Kρ denotes for a Gaussian kernel with standard deviation ρ, I denotes for the intensity field of DSA images, ∇3I=[Ix, Iy, It]T, denoting for the gradient of the intensity field of DSA images, wherein
• I
• x
• =
• ∂
• I
• ∂
• x
• ,
• I
• y
• =
• ∂
• I
• ∂
• y
• ⁢
• ⁢
• and
• ⁢
• ⁢
• I
• t
• =
• ∂
• I
• ∂
• t
• ,
• x and y denote for a two-dimensional spatial position, t denotes for a time.