Assessment of Diastolic Function Using Ultrasound Elastography.

Shear wave elasticity imaging (SWEI) is a novel ultrasound elastography technique for assessing tissue stiffness. In this study, we investigate the potential of SWEI for providing diastolic functional assessment. In 11 isolated rabbit hearts, pressure-volume (PV) measurements were recorded simultaneously with SWEI recordings from the left ventricle free wall before and after induction of global ischemia. PV-based end diastolic stiffness increased by 100% after ischemia (p <0.05), and SWEI stiffness showed an increase of 103% (p <0.05). The relaxation time constant (τ) before and after ischemia derived from pressure and SWEI curves showed increases of 79% and 76%, respectively (p <0.05). A linear regression between pressure-derived and SWEI-based (τ) showed a slope of 1.164 with R2 = 0.80, indicating the near equivalence of the two assessments. SWEI can be used to derive (τ) values and myocardial end diastolic stiffness. In global conditions, these measurements are consistent with PV measurements of diastolic function.