Systems and methods are provided for mapping myocardial tissue architecture based on diffusion tensor imaging (DTI). A set of eigenvectors is derived from diffusion tensor data, where each eigenvector describes the diffusion of spins along one of the Cartesian directions. A radial coordinate axis and a circumferential plane are determined based on anatomical information of the subject, such as from an image depicting the epicardial surface of the subject's heart, A longitudinal coordinate axis and a circumferential coordinate axis are determined based on the radial coordinate axis and circumferential plane, A fiber architecture matrix (FAM) is then computed for locations in the subject's heart based on projecting the set of eigenvectors onto a local coordinate system defined by the circumferential, radial, and longitudinal axes, Maps that represent myocardial tissue architecture can then be generated using the FAM for locations within the subject's heart.