1. A method for modeling tissue motion, comprising: providing a plurality of digitized images of a portion of patient tissue, said plurality of digitized images comprising successive frames representing motion of said tissue; performing spatiotemporal phase unwrapping of the frames; calculating displacement vectors for all pixels of all frames; defining a portion of the tissue at any one frame; using a modulus deformation mask to remove all displacement vectors with deformation above a predetermined amount; for the displacement vectors at each frame having deformation below said predetermined amount, finding a predetermined number of closest vector tails of said displacement vectors to each identified tissue position at time=0; calculating how much each displacement vector differs from a mean magnitude and angle of the predetermined number of closest vector tails; ignoring displacement vectors with an angle deviation greater than a predetermined number of radians and a predetermined magnitude deviation from the mean magnitude; selecting the three closest vector tails of the remaining vector tails and using the three closest vector tails for a 2D interpolation; representing trajectory position at each frame by a 2D Gaussian function with an area of unity and a standard deviation, and then obtaining a binary mask for each frame by thresholding the associated frame image at 0.5; obtaining isocontours based on the binary images resulting from the binary mask; designating the longest isocontour as an outer tissue portion and the second longest isocontour as an inner tissue portion; and smoothing the contours by fitting periodic functions as a function of arc length.