Regional epicardial dynamics computed from coronary cineangiograms

A method to compute the region epicardial deformation from coronary cineangiograms is presented. For this purpose, a close relationship is assumed between the motion of the epicardium and the motion of the embedded coronary arterial tree which is visible on cineangiograms. The interframe motion of the coronary arteries is computed by an optical flow approach assuming a locally linear two-dimensional (2-D) motion field. One can thus extract from the composite linear field meaningful components, such as the local 2-D biaxial deformation of the epicardial surface and the related epicardial thickening. Once the region of interest (ROI) is selected, the method is essentially operator free and provides a tool to characterize the epicardial dynamics. The method is five to ten times faster than conventional iterative optical flow methods, while providing essentially the same results. The method was applied to monoplane angiography, using a projection with the ROI parallel to the image plane (to minimize the foreshortening) to reduce the effect of third-dimension movement on the computed deformation field