Estimation of the left ventricle 3-D motion from single plane cineangiograms

The authors propose a new approach to evaluate the ventricle dynamics in monoplane ventriculography. The approach is divided into two main steps. First, the 2-D image plane motion (x, y motions) of the heart is evaluated and next the depth motion (z-motion) is assessed. To compute the x, y motion an optical flow method is used. This method is applied to the segmented ventriculograms that are obtained by setting to 0 and 1 the exterior and interior, respectively, of the ventricle using an edge detection algorithm. The optical flow was used to warp one ventriculogram into the next, making the ventricle contours meet exactly. If it is assumed that the contrast medium has a constant concentration and is uniformly distributed in the ventricle, then the brightness difference between the aligned ventriculograms is directly related to the z-motion. Using gray-level images to display this third component of the ventricle motion, it is possible to produce an animation of the 3-D motion of the left ventricle. Results are presented for an ellipsoid model undergoing translation and expansion-contraction as well as for a cineangiogram sequence of a human heart