Physical models for measurement of blood velocity and flow from diagnostic images

The authors present preliminary results and new technical developments in measurement of cross-sectional blood velocities and flow from a time-sequence of arteriograms. They apply the conservation of mass principle to flowing blood and the injected contrast medium in a vessel in order to obtain mathematical constraints on cross sectional velocities from a sequence of contrast-injected images. The previously employed optical flow constraint discussed by Mongrain et al. (Computers in Cardiology, 1991) and other authors is found to be a special case of this constraint. The proposed framework is also particularly efficient. The numerical methods compute a stream function (a single image) from a window of images in a time-sequence, and in a post-processing step, the cross-sectional velocity field is determined simply by application, of a gradient operator to the stream function