Increasing the realism of in silico cortex substrates for diffusion MRI simulation

Motivation: Virtual microstructure has been one of the promising approaches to study and validate diffusion MRI microstructure models. Previous works in generating synthetic substrates have only focused on specific cell types, i.e. axons, neurons. Goal(s): The main goal of this work is to advance modeling of virtual gray matter microstructure and to close the real to simulation gap in brain microstructure geometries. Approach: We extend a framework of microstructure modeling to generate hybrid substrates that combine purely synthetic cells with virtual cells reconstructed from histology. Results: Different virtual substrates have been generated with axons and neurons with similar volume fractions in human cortex. Impact: More realistic virtual microstructure can allow the development of new computational models to map microstructure from diffusion MRI data. It can also be used to validate a whole set of analytical models and evaluate their accuracy.