Acoustoelasticity in soft solids: Assessment of the nonlinear shear modulus with the acoustic radiation force

Abstract

The assessment of viscoelastic properties of soft tissues is enjoying a growing interest in the field of medical imaging as pathologies are often correlated with a local change of stiffness. To date, advanced techniques in that field have been concentrating on the estimation of the second order elastic modulus (mu). In this paper, the nonlinear behavior of quasi-incompressible soft solids is investigated using the supersonic shear imaging technique based on the remote generation of polarized plane shear waves in tissues induced by the acoustic radiation force. Applying a theoretical approach of the strain energy in soft solid [Hamilton et al., J. Acoust. Soc. Am. 116, 41-44 (2004)], it is shown that the well-known acoustoelasticity experiment allowing the recovery of higher order elastic moduli can be greatly simplified. Experimentally, it requires measurements of the local speed of polarized plane shear waves in a statically and uniaxially stressed isotropic medium. These shear wave speed estimates are obtained by imaging the shear wave propagation in soft media with an ultrafast echographic scanner. In this situation, the uniaxial static stress induces anisotropy due to the nonlinear effects and results in a change of shear wave speed. Then the third order elastic modulus (A) is measured in agar-gelatin-based phantoms and polyvinyl alcohol based phantoms.

Quantification of elasticity changes in the myometrium during labor using Supersonic Shear Imaging: A feasibility study

“…Regarding the latter, changes in shear wave speed can only be due to a change of uniaxial stress [20], which is certainly not the case here, but this would require more investigation. Not differentiating between the intrinsic stiffness and elastic nonlinearities constitutes a limitation of this study.…”

Value of ultrasound elastography in the diagnosis of native kidney fibrosis.

“…The shear wave velocity measurement is also the principle of the most advanced type of US elastography -Supersonic Shear Imaging (SSI) [13,14]. In SSI technology, a supersonic shear wave source is generated within the tissue, the amplitude of shear waves being increased while limiting the acoustic power; multiple radiation beam pushes can be successively focused at different points in the examined tissue and they generate a shear wave with a supersonic speed [13,15].…”

A finite element model to study the effect of tissue anisotropy onex vivoarterial shear wave elastography measurements

“…Analytical studies of SW propagation in stressed bulk linear elastic media (Gennisson et al, 2008;Destrade et al, 2010b;Abiza et al, 2012) or general anisotropic/transverse isotropic bulk media (Destrade et al, 2010a;Cheviakov & Ganghoffer, 2015;Shams et al, 2011) were previously performed. These studies did not focus on the SW propagation within restricting boundaries of the plate and considering the orthotropic material.…”