A Preliminary Investigation of Traumatically Induced Axonal Injury in a Three-Dimensional (3-D) Finite Element Model (FEM) of the Human Head During Blast-Loading

In the context of recent military conflicts and the prevalence of improvised explosive devices (IEDs), there has been an eminent need to better understand the mechanisms of brain injury resulting from blast exposure of military personnel. In this study, Diffusion Tensor Imaging (DTI) was used to inform a human head finite element model (FEM) to create a transversely isotropic description of the white matter fiber tissue. For each element in the model that spatially occupied the same regions as the white matter fiber tractography, the strain was calculated in the direction of the axonal fiber bundles. The axonal strain was used to predict the prevalence of diffuse axonal injury in blast events. It was found that the presence of axonal strains above a critical threshold were widespread, and the maximal axonal strains in the white matter tissue occur long after (10 20 ms) the initial shock wave has been applied to the head. Maximum axonal strains and shear stress values were increased due to brain tissue deformation from head rotation. The original document contains color images.