Investigation of diffuse axonal injury induced by rotational acceleration via numerical reconstructions of in vivo rat head impact experiments

Journal article, 2015

The purpose of this study is to investigate the brain-strain-based thresholds for better prediction of the diffuse axonal injury (DAI) induced by a rotational acceleration on the rat brain. A previously developed and validated rat head finite element model was used to reconstruct 26 in vivo rat head impact experiments. DAI was produced via the high rotational acceleration applied to the rat head on the sagittal plane. Intracranial strain and strain-based injury indexes were calculated, including the maximum principal strain (MPS), the product of strain and strain rate, and the cumulative strain damage measure (CSDM). The region-specific conservative thresholds for DAI were estimated in terms of strain and strain-based injury indexes in the frontal, middle, and occipital regions of the corpus callosum. The axonal injuries observed in the experiments were used to formulate the injury risk functions, and the DAI risks were analysed via binary logistic regressions in terms of the calculated injury indexes. The logistic regression analysis demonstrated that the MPS, the product of strain and strain rate, as well as the CSDM were significantly correlated with DAI in the frontal corpus callosum. For the 50% probability of DAI in the frontal corpus callosum, it is suggested that the strain-based threshold is 0.12 for the MPS, 110 s ¡1 for the product of strain and strain rate, and 17% for the CSDM.