Figure 11

Example of out of plane motion of the region of interest. Diastolic circumference of the RV (L₀) is obtained on the mid-ventricular level (B). Since the scanning plane doesn’t move, while heart tissue is displaced apically during contraction, the systolic circumference is obtained (D) from an initially more basal located RV level. Absolute circumferential Lagrangian strain (CS) is based on the circumference measurements and calculated as CS = 100%*(diastolic-systolic)/diastolic. Therefore, the CS values based on measured systolic circumference are falsely reduced. This effect is exaggerated with higher longitudinal displacement (as is the case in healthy controls compared to patients with tetralogy of Fallot).