IMAGING AND ANALYSIS FOR DETERMINATION OF CARDIOVASCULAR MECHANICS

Overview of two projects related to determination of in-vivo physiology in the cardiovascular system from magnetic resonance is given. In one instance, we describe a recently developed technique for determining intravascular pressures from MR velocity data which offers advantages over previously proposed approaches. This technique performs harmonics-based orthogonal projection of noisy pressure gradients computed from pulsatile velocity data based on the Navier-Stokes equation onto an integrable subspace and results in a valid dynamic scalar pressure field. In a second instance, an improved framework for estimation of 3-D left-ventricular deformations from tagged MRI is described. Contiguous short- and long-axis tagged MR images are collected and are used within a 4-D B-spline based deformable model to determine 4-D displacements and strains. The framework entails use of both tagged images and 2-D dense displacements obtained from band-pass phase information