Choukri Mekkaoui1, Sonia Nielles-Vallespin2, Marcel Parolin Jackowski3, Timothy G. Reese4, Peter David Gatehouse2, David N. Firmin5, David E. Sosnovik4
1Harvard Medical School - Massachusetts General Hospital - Athinoula A Martinos center for Biomedical, Boston, MA, United States; 2CMR Unit, Royal Brompton Hospital, London, United Kingdom; 3University of So Paulo, So Paulo, Brazil; 4Harvard Medical School - Massachusetts General Hospital - Athinoula A Martinos center for Biomedical, Charlestown, MA, United States; 5CMR Unit, Royal Brompton Hospital, London, United States
In vivo Diffusion Tensor MRI (DTI) of the human heart has shown that myofiber architecture is dynamic. However, most architecture-related indices derived from the diffusion tensor have relied solely upon information from the principal eigenvector. Here we introduce the fiber architecture matrix (FAM), which encodes myofiber architecture by the angles of the projections of all three diffusion tensor eigenvectors onto the orthogonal planes of the cardiac coordinate system. Angular variations across the LV wall are seen for all FAM coefficients while the greatest changes between systole and diastole are seen in the elements of the matrix describing sheet architecture.