Fig. 1.

Definition of eigenvectors, angles, and segments. A: Single tensor, displayed as a superquadric glyph, shows the orientation of the principal eigenvectors v₁, v₂ and v₃. B: The helix angle (HA) of a given eigenvector is the angle subtended by the projection of the eigenvector onto the tangential plane and the short-axis plane. The transverse angle (TA) is the angle subtended by the projection of the eigenvector onto the short-axis plane and the tangential plane. C: Specification of regions-of-interest in the LV anterior, lateral, posterior and septal walls (LVA, LVL, LVP and LVS) based on the angle θ, perpendicular to the long-axis centred in the LV cavity. The RV anterior, lateral and posterior walls (RVA, RVL, RVP) were similarly specified based on a long-axis centred on the union of the LV septum and cavity and the RV cavity.