Department of Mechanical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2682, USA.
J Neurotrauma. 2013 Jan 15;30(2):102-18. doi: 10.1089/neu.2012.2418.
A computational modeling framework is developed to estimate the location and degree of diffuse axonal injury (DAI) under inertial loading of the head. DAI is one of the most common pathological features of traumatic brain injury and is characterized by damage to the neural axons in the white matter regions of the brain. We incorporate the microstructure of the white matter (i.e., the fiber orientations and fiber dispersion) through the use of diffusion tensor imaging (DTI), and model the white matter with an anisotropic, hyper-viscoelastic constitutive model. The extent of DAI is estimated using an axonal strain injury criterion. A novel injury analysis method is developed to quantify the degree of axonal damage in the fiber tracts of the brain and identify the tracts that are at the greatest risk for functional failure. Our modeling framework is applied to analyze DAI in a real-life ice hockey incident that resulted in concussive injury. To simulate the impact, two-dimensional finite element (FE) models of the head were constructed from detailed MRI and DTI data and validated using available human head experimental data. Acceleration loading curves from accident reconstruction data were then applied to the FE models. The rotational (rather than translational) accelerations were shown to dominate the injury response, which is consistent with previous studies. Through this accident reconstruction, we demonstrate a conceptual framework to estimate the degree of axonal injury in the fiber tracts of the human brain, enabling the future development of relationships between computational simulation and neurocognitive impairment.
我们开发了一种计算建模框架，用于估算头部惯性载荷下弥漫性轴索损伤（DAI）的位置和程度。DAI 是创伤性脑损伤最常见的病理特征之一，其特征是大脑白质区域的神经轴突受损。我们通过使用弥散张量成像（DTI）来整合白质的微观结构（即纤维方向和纤维分散），并使用各向异性超粘弹性本构模型来模拟白质。通过轴突应变损伤准则来估计 DAI 的程度。我们开发了一种新的损伤分析方法，用于量化大脑纤维束中轴突损伤的程度，并确定最容易发生功能故障的纤维束。我们的建模框架应用于分析导致脑震荡损伤的真实冰球事故中的 DAI。为了模拟撞击，我们根据详细的 MRI 和 DTI 数据构建了头部的二维有限元（FE）模型，并使用现有的人类头部实验数据进行了验证。然后将事故重建数据中的加速度加载曲线应用于 FE 模型。结果表明，旋转（而不是平移）加速度主导着损伤反应，这与之前的研究一致。通过这次事故重建，我们展示了一种估算人类大脑纤维束中轴突损伤程度的概念框架，为计算模拟与神经认知障碍之间的关系的未来发展奠定了基础。
