Quantitative myocardial kinetic energy as physiological parameter in cine-MRI

It is a fundamental goal in many modalities of cardiac imaging to measure the global and regional function of the left ventricle through wall motion, thickening and strain, in an effort to isolate the location, severity and extent of ischemic or infarcted myocardium. However, proper characterization of the heart complex motion still remains an open and challenging research problem. Optical flow (OF), the velocity vector field corresponding to the observed motion of brightness patterns in sequences of images, is an important quantity in a variety of problems in computer vision. In magnetic resonance images of the heart this field may provide diagnostic information concerning cardiac muscle motion. A common basic problem in estimating OF concerns how to compute derivative approximations from discrete data. It is, however, well known that derivative estimation is not a well-posed problem. Derivative estimators usually enhance the noise and some sort of smoothing in the data is necessary. This work describes a method to compute OF in 3D using the scale-space approach. The method was applied to cine MR images. A set of ten normal subjects was analyzed in terms of myocardial kinetic energy and ejection fraction.