Reconstruction and Visualization of Fiber and Laminar Structure in the Normal Human Heart from Ex Vivo DTMRI Data

(148 words) Objective: The human heart is composed of a helical network of muscle fibers organized to form sheets that are separated by cleavage surfaces responsible for the orthotropic mechanical properties of cardiac muscle. The purpose of this study is the visualization of these structures in three dimensions. Methods: Anisotropic least square filtering followed by fiber and sheet tracking techniques were applied to Diffusion Tensor Magnetic Resonance Imaging data of the excised human heart. The sheets were reconstructed by surfaces that we defined locally from the second and third eigenvector of the diffusion tensor. Results: The fibers are shown to lie in sheets that have transmural structure which correspond to histological studies published in the literature. Quantitative measurements show that the sheets are organized into laminar orientations of two dominant populations. Conclusions: A visualization algorithm was developed to demonstrate the complex three-dimensional orientation of the fibers and sheets in human myocardium.