Displacement-Encoded MRI With Steady-State Acquisition for Deformations and Strains in Applied Load Systems

Noninvasive and nondestructive methods like magnetic resonance imaging (MRI) used to visualize tissue mechanical behavior are key to understanding its material properties and function. Displacement-encoded MRI [1] has allowed for biomechanics research in the myocardium and other self-actuated tissues. However, additional imaging constraints must be considered when external loading must be applied to reproduce physiologically relevant loads and deformations in a tissue of interest. Previous studies have used displacement encoding with stimulated echoes (DENSE) with a fast spin echo (FSE) acquisition [2]. Despite a measured sub-pixel displacement resolution (65 μm [3]), DENSE-FSE is limited by long imaging times and signal-to-noise (SNR). Balanced steady state free precession acquisitions like true fast imaging with steady state precession (TrueFISP), however, provide high SNR and can be modified for DENSE acquisition [4]. Here, we evaluate DENSE with TrueFISP readout for noninvasive and rapid acquisition of deformation data in biomechanical systems that require exogenous applied loading.