Micro-anisotropy and time-dependent diffusion in the mouse brain in vivo with spherical tensor encoding and the spectral principal axis system

Accounting for time-dependent diffusion (TDD) in tensor-valued encoding is required for unbiased assessment of microscopic anisotropy (µA). We have previously introduced the spectral principle axis system (SPAS) to find linear tensor encoding (LTE) projections of spherical tensor encoding (STE) with maximum spread of sensitivity to TDD. This can be used to simultaneously achieve unbiased µA and TDD contrasts within a single protocol. Here we present results from in vivo experiments in a mouse brain. The two independent contrasts (µA- TDD) indicate consistent variations in different brain regions.