On the importance of using region-dependent material parameters for full-scale human brain simulations

An accurate finite element (FE) model of the human brain reliably predicting its response to loading offers great possibilities for brain injury prevention, disease prediction, and surgical guidance. However, the brain is a very complex organ. One important aspect is the structural heterogeneity, both on a macroscopic and microscopic level. This also results in heterogeneous mechanical properties, which highly depend on the brain regions. The extent to which this heterogeneity affects the mechanical response of an FE simulated full brain remains largely unexplored. In this work, we investigate the importance of using region-specific material parameters when modelling the full human brain. Additionally, we assess how a prefixed Poisson’s ratio used for the determination of regional parameters affects the response of the full brain under loading. Finally, we compare the simulation results when using parameter sets that have been determined from the unconditioned and preconditioned behaviour of human brain tissue. Our results show that accounting for region-dependent properties leads to significant differences in the predicted strain state compared to simulations assuming homogeneous material properties. Also the Poisson’s ratio and using unconditioned or preconditioned data sets significantly affects the results of full-scale brain simulations, highlighting the importance of carefully selecting the material parameters used. The presented analyses have important implications for choosing appropriate region-dependent material parameters for full-scale FE human brain simulations in the future to ensure reliable predictions.