The movement over the cardiac cycle of a set of LV surface points is performed by following local surface shape. As a first step in the tracking algorithm, endocardial and epicardial surfaces at one given time instant are used as references and are subsampled, creating a sparser set(about five percent of the total points) of points which are then followed over time under a bending model. The motion trajectories of all the points on the surfaces, the dense motion vector field, can be found through a vector field smoothing-interpolating process.