Figure 1
Illustration of the measurements obtained from tagged MR. Consecutive tagged short-axis planes were acquired from apex to base. On each short-axis plane, radial thickening (Err, purple) and circumferential shortening strain (Ecc, blue) were computed and the average of Err and Ecc for the entire left ventricle was recorded. Rotation of the most basal (red) and apical slice (green) slices were computed and left ventricular torsion (orange) was calculated as difference between apical and basal rotation divided by the length (l) between apex and base and multiplied by the mean radius of the base (rbase) and apex (rapex) to obtain LV twist (φ). The first derivate of LV twist over time was respectively systolic twist rate and diastolic untwist rate.