Dynamic and quantitative assessment of myocardial stiffness using Shear Wave Imaging

Shear Wave Imaging was used to assess the myocardial stiffness in Langendorff perfused rat heart. This technique was used to quantify the myocardial stiffness and its dynamics over the cardiac cycle. This method is based on the generation of a shear wave (typically in the kHz range) that propagates in soft tissues at a velocity of a few meters per second that is linked to the tissue stiffness. The acquisition of the shear wave propagation was performed in less than 10 ms, enabling the possibility to follow dynamically the variation of the myocardial stiffness during the cardiac cycle. The feasibility of imaging the myocardial elasticity was demonstrated up to 15 times per cardiac cycle. The mean shear wave velocity was found to be 3.8 ± 0.6 m/s in the systolic phase and 1.1 ± 0.15 m/s in the diastolic phase when the probe was set in the long axis orientation.