Ultrasound Elastography for Biomedical Applications and Medicine

34 Musculoskeletal Applications of Supersonic Shear Imaging

Jean‐Luc Gennisson

Imagerie par Résonance Magnétique Médicale et Multi‐Modalités, Université Paris‐Saclay, Orsay, France

34.1 Introduction

In vivo muscle biomechanical properties have been classically inferred from inverse dynamics or measurements of joint torque performed using ergometers. However, these measures provide information about the combined behavior of several structures, such as muscles, tendons, nerves, and skin, all acting around a given joint. To isolate the behavior of an individual muscle is highly complicated. Since the introduction of elastography in the 1990s, many techniques have been developed with the aim to noninvasively assess localized muscle stiffness. In this chapter we focus on the supersonic shear imaging technique in musculoskeletal applications. As described in Chapter of this book, this technique allows one to recover locally the stiffness of an organ by looking at the propagation of shear waves. Since propagation velocity is directly linked to the shear elastic modulus of the tissue, the stiffer the tissue, the faster the shear wave propagation (Eq. 34.1).

(34.1)

where μ is the shear elastic modulus of the tissue, ρ is the density of muscle (1000 kg/m³), and V _s is the shear wave velocity.

However, for the study of muscle biomechanics the relevance of the shear elastic ...