In shear wave elastography, rotational wave speeds are converted to elasticity measures using elastodynamic theory. The method has a wide range of applications and is the gold standard for non-invasive liver fibrosis detection. However, the observed shear wave dispersion of in vivo human liver shows a mismatch with purely elastic and visco-elastic wave propagation theory. In a laboratory phantom experiment we demonstrate that porosity and fluid viscosity need to be considered to properly convert shear wave speeds to elasticity in soft porous materials. We extend this conclusion to the clinical application of liver stiffness characterization by revisiting in vivo studies of liver elastography. To that end we compare Biot’s theory of poro-visco-elastic wave propagation to Voigt’s visco-elastic model. Our results suggest that accounting for dispersion due to fluid viscosity could improve shear wave imaging in the liver and other highly vascularized organs.

在剪切波弹性成像中，使用弹性动力学理论将旋转波速度转换为弹性测量。该方法应用广泛，是无创肝纤维化检测的金标准。然而，观察到的横波色散体内人类肝脏与纯弹性和粘弹性波传播理论不匹配。在实验室虚拟实验中，我们证明需要考虑孔隙率和流体粘度，才能将软质多孔材料中的剪切波速度正确转换为弹性。我们通过重新审视这一结论，将这一结论扩展到肝脏硬度表征的临床应用体内肝脏弹性成像研究。为此，我们将 Biot 的多孔粘弹性波传播理论与 Voigt 的粘弹性模型进行了比较。我们的结果表明，考虑到由于流体粘度引起的弥散可以改善肝脏和其他高度血管化器官中的剪切波成像。