Tracking myocardial beads from SPAMM-MRI with a 4-D B-spline model

A 4-D B-spline model has been created to accurately capture the dynamic motion of the heart from tagged magnetic resonance imaging (MRI). The knot planes of the 4-D B-spline model surfaces deform to fit three orthogonal sets of tag surfaces for all frames within the constraints of the model´s spatio-temporal internal energy. As an important byproduct, the points defined by the three-dimensional (3-D) intersections of the three sets of orthogonal tag planes, which we refer to as myocardial beads, can easily be determined by our model. Displaying the beads as a movie loop as a function of time allows for the visualization of the non-rigid movement of the left ventricle. Results are shown from both simulated data produced by a cardiac motion simulator as well as in-vivo pig data.