Ultrasound Elastography for Biomedical Applications and Medicine

19 Shear Wave Dispersion Ultrasound Vibrometry

Pengfei Song and Shigao Chen

Department of Radiology, Mayo Clinic, Rochester, MN, USA

19.1 Introduction

This chapter introduces an ultrasound imaging method called shear wave dispersion ultrasound vibrometry (SDUV) that can quantify both tissue elasticity and viscosity noninvasively. SDUV generates multi‐frequency wide‐band harmonic shear waves using both acoustic radiation force (ARF) and external mechanical vibration to obtain the shear wave speed dispersion curve, from which tissue viscoelasticity can be robustly estimated [1, 2]. SDUV has been used on a variety of ex vivo and in vivo tissues including liver, heart, artery, kidney, prostate, and muscle. In this chapter we will first provide reviews of the principles of the SDUV technique, followed by brief reviews of existing clinical applications of SDUV.

19.2 Principles of Shear Wave Dispersion Ultrasound Vibrometry (SDUV)

Shear wave speed (c _s) in a homogeneous Voigt medium depends on the frequency of the shear wave ω _s

(19.1)

where ρ, μ ₁, and μ ₂ are the density, shear elasticity, and shear viscosity of the medium, respectively [1]. The density of the soft tissue can be assumed to be 1000 kg/m³. If shear wave speed at multiple frequencies can be measured (i.e. a shear wave dispersion curve can be obtained), one can calculate both μ ₁ and μ ₂ by fitting ...