Computation of axonal elongations: towards a new brain injury criterion

Abstract

Finite element head models are a well-known way to describe the intracerebral mechanical behaviour during a head impact and, hence, to develop diffuse axonal injury (DAI) prediction tools. Owing to the lack of experimental data, the brain model is usually considered as homogeneous and isotropic. This hypothesis is acceptable from a mechanical point of view, but the classical computed metrics are not adequate according to the varying vulnerability of the neurological cells in the brain. The present study aims to show that the brain axonal orientations map provided by diffusion MRI can be combined with the computed strains in order to evaluate axonal elongations. This new metric seems to be more representative of the DAI mechanisms, which are known to be due to axon elongation.