Random Walks in the Model Brain Tissue: Monte Carlo Simulations and Implications for Diffusion Imaging

Farida Grinberg¹, Yuliya Kupriyanova¹, Ana-Maria Oros-Peusquens¹, N Jon Shah^1,2

The propagation of water molecules in the brain and the corresponding NMR response are affected by many factors such as compartmentalization, restrictions, and anisotropy imposed by the cellular microstructure. In addition, interfacial interactions with the cell membranes and exchange play a role. Therefore, a differentiation between the various contributions to the average NMR signal in in vivo studies represents a difficult task. In this work, we have performed random-walk Monte Carlo simulations in model systems aiming at establishing the quantitative relations between the dynamics and microstructure. A detailed analysis of the average diffusion propagators and the corresponding signal attenuations is presented and the implications for experimental studies are discussed.