This paper develops an energy minimization algorithm to reconstruct the 3D motion of transplanted hearts of small animals (rats) from tagged magnetic resonance (MR) sequences. We describe the heart by a layered aggregate of thin oriented elastic fibers. We use the orientation of myocardial fibers to develop a local dense motion of the heart. This dense model is fit to the tagged MRI data by minimizing an energy functional with two terms: the first term is the external energy, derived from matching the image intensities on the fibers across two consecutive frames; the second term is the fibers' internal energy, derived from biomechanics analysis. This paper illustrates the application of the approach to a set of cardiac MR sequences containing four slices of a transplanted rat heart.
Chien Ho, Hsun-Hsien Chang, José M. F. Mour