  This study aims to validate if MRI can measure anisotropic mesoscopic Larmor
frequency shifts from white matter axonal microstructure relative to the B0
direction and if dMRI can estimate this anisotropy. Recent models describe how
mesoscopic Larmor frequency shifts depend on induced magnetic fields by axons,
described by an orientation distribution function. Using Monte-Carlo
simulations of MRI signals in mesoscopic white matter axon substrates, we show
MRI can estimate this mesoscopic frequency shift and dMRI can estimate its
orientation dependence.
