Magnetic Resonance Elastography by Direct Visualization of Propagating Acoustic Strain Waves

TLDR

The study introduces an MRI method to quantitatively map a material’s response to harmonic mechanical excitation. This is achieved by imaging the propagation of acoustic strain waves using nuclear magnetic resonance imaging. The MRI technique yields images that enable calculation of regional mechanical properties, with shear modulus measurements in gels correlating with static values, detecting sub‑200‑nm displacement patterns, and demonstrating feasibility for imaging tissue elasticity.

Abstract

A nuclear magnetic resonance imaging (MRI) method is presented for quantitatively mapping the physical response of a material to harmonic mechanical excitation. The resulting images allow calculation of regional mechanical properties. Measurements of shear modulus obtained with the MRI technique in gel materials correlate with independent measurements of static shear modulus. The results indicate that displacement patterns corresponding to cyclic displacements smaller than 200 nanometers can be measured. The findings suggest the feasibility of a medical imaging technique for delineating elasticity and other mechanical properties of tissue.