Fig. 3.

3D-strain. The figures show deformation including shear strain. L₀ means a baseline length between endo- and epicardium. Radial strain is calculated as (Lr - L₀) / L₀. If the shear (α degree) is caused between radial and longitudinal direction, the shear (β degree) is caused between radial and circumferential direction, and without shear between circumferential and longitudinal direction, the length between estimated endo- and epicardial points at end-systole is L. The novel parameter 3D-strain is calculated as (L - L₀) / L₀, then, 3D-strain is greater than 3D-radial strain because L is longer than Lr.