Figure 4

LV feature tracking analysis (1) Iidentify end-diastolic phase (reference phase); (2) The endo- and epicardial borders were automatically drew in the end-diastolic phase using SAX slices (a-e) and long axis 2-, 3- and 4-chamber slices (f–h), which could be manually adjusted if poor tracking; (3) Then, the software algorithm automatically drew the borders and traced the myocardium voxel points throughout the other cardiac phases during a cardiac cycle based on the endo- and epicardial contours of reference phase; (4) Finally, the 2D strain values were calculated automatically.