Connecting Diffusion Tensor Information with Mechanical Anisotropy of a Hyper-Viscoelastic Constitutive Model for Brain Tissue

This study aims to test the mechanical behavior of a hyper-viscoelastic fiber-reinforced material for brain tissue which accounts for anisotropic features of the brain thereby exploiting imaging. The degree of anisotropy of axonal fibers and their orientation are integrated into an existing finite element head model; subsequently, calculations of tissue loads and deformation patterns are performed in order to identify possible relationships between a particular deformation in a tissue and an injury in the same. Through the use of , a concussive impact between two football players is simulated ( Case Study ) and the biomechanics of the struck player’s head is analyzed. Mechanical measures such as principal strain, strain rate and anisotropic equivalent strain are computed and a correlation between internal microscopic structure and macroscopic mechanical properties is investigated. Results of the research show that especially white matter mechanical behavior is dependent on the primary orientation and the angular distribution of axonal fibers. The inclusion of anisotropy into a constitutive model for brain tissue has a significant effect on the predicted injury locations when tissue-level measures such as maximum principal strain or anisotropic equivalent strain are used as injury criteria. Indeed this study confirms that the coupling method imaging – model is an innovative and promising possibility to improve bio-fidelity of head finite element simulations