8 Characterization of Skeletal Muscle Elasticity Using Magnetic Resonance Elastography

Magnetic resonance elastography (MRE) is a non-invasive phase-contrast MR technique that directly visualizes and quantitatively measure propagating strain waves in tissue-like materials subject to harmonic mechanical excitation. A phase-contrast MRI technique is used to spatially map the shear wave displacement field, and local quantitative values of shear modulus are then calculated through various inversion algorithms, and elastogram generated. This information can be clinically useful to understand the effects of pathologies on the mechanical properties of skeletal muscle and to quantify the effects of treatment. In this chapter, the principles of MRE image acquisition and stiffness inversion algorithm are reviewed, specific instrumention to apply MRE on skeletal muscles are introduced, and unique challenges to MRE when applied on skeletal muscles are discussed.