System and method for diagnosing brain conditions including evaluating fiber pathways of white matter tracts using a diffusion tensor imaging (DTI) process, tracking the propagation of waves traveling at specific angles to the fiber pathways by performing a 3D magnetic resonance elastography (MRE) process at the same spatial resolution and voxel position as the DTI, analyzing the viscoelastic properties using an inversion having at least nine elastic coefficients, determining the curvature along the pathways, differentiating the spatial-spectral filter twice with respect to arc length along the pathways, and diagnosing a brain condition based on the viscoelastic properties.