Simultaneous Acquisition of Magnetic Resonance Elastography ( MRE ) and Diffusion Tensor Imaging ( DTI ) Optimized for Human Brain

PURPOSE: Increase clinical acceptance of MRE and DTI by shortening the scan time by half and providing diffusive and mechanical property maps that are inherently co-registered. This proof-of-concept study evaluates the simultaneous DTI-MRE acquisition in the human brain and compares its results to conventional DTI and MRE measurements. METHODS: We optimized experimental parameters for in vivo human brain DTI-MRE acquisitions based on signal-to-noise ratio, encoding efficiency, and intravoxel phase dispersion mitigation. Five healthy subjects underwent scanning on a 3 T Siemens Prisma scanner, using two optimized parameter sets. Diffusive (mean diffusivity, fractional anisotropy) and mechanical (shear stiffness) property maps were computed and compared with conventional methods using Pearson's correlation analysis. RESULTS: DTI-MRE correlated with conventional DTI and MRE methods across all subjects. Mean diffusivity and fractional anisotropy maps showed excellent fidelity between methods (Pearson's coefficients of global mean values > 0.86, Pearson's coefficients of voxel-wise values > 0.7). Spatially averaged shear stiffness values were slightly lower in DTI-MRE. CONCLUSION: This proof-of-concept study confirms the feasibility of simultaneous DTI-MRE acquisition in the human brain, offering an efficient method for obtaining both diffusive and mechanical property maps. Further refinements in encoding strategies and inversion algorithms, such as the incorporation of a multi-frequency actuation approach in the DTI-MRE framework, could enhance accuracy, enabling broader clinical applications in neurology, neurosurgery, and brain injury assessment.