On the anisotropy of IVIM-derived microvascular cerebral pseudo-diffusion: a physics-informed neural network approach

Acquisition of intravoxel incoherent motion (IVIM) images with diffusion sensitization in at least six directions (IVIM tensor imaging) provides the unique opportunity to non-invasively measure the anisotropy of both the parenchymal and microvascular diffusivity ( D and D* ). We demonstrate the feasibility of whole-brain IVIM tensor analysis by utilizing a physics-informed neural network fitting approach to achieve more accurate assessment of D , D* , and the corresponding tensors. The fractional anisotropy of D* (FA( D* )) was explored for different brain tissue regions, which revealed lower FA( D* ) in cortical gray matter and higher FA( D* ) in deep gray matter compared to white matter.