Finite element models (FEMs) are used increasingly in the traumatic brain injury (TBI) field to provide an estimation of tissue responses and predict the probability of sustaining TBI after a biomechanical event. However, FEM studies have mainly focused on predicting the absence/presence of TBI rather than estimating the location of injury. In this study, we created a multi-scale FEM of the pig brain with embedded axonal tracts to estimate the sites of acute (≤6 h) traumatic axonal injury (TAI) after rapid head rotation. We examined three finite element (FE)-derived metrics related to the axonal bundle deformation and three FE-derived metrics based on brain tissue deformation for prediction of acute TAI location. Rapid head rotations were performed in pigs, and TAI neuropathological maps were generated and colocalized to the FEM. The distributions of the FEM-derived brain/axonal deformations spatially correlate with the locations of acute TAI. For each of the six metric candidates, we examined a matrix of different injury thresholds (th_x) and distance to actual TAI sites (d_s) to maximize the average of two optimization criteria. Three axonal deformation-related TAI candidates predicted the sites of acute TAI within 2.5 mm, but no brain tissue metric succeeded. The optimal range of thresholds for maximum axonal strain, maximum axonal strain rate, and maximum product of axonal strain and strain rate were 0.08–0.14, 40–90, and 2.0–7.5 s⁻¹, respectively. The upper bounds of these thresholds resulted in higher true-positive prediction rate. In summary, this study confirmed the hypothesis that the large axonal-bundle deformations occur on/close to the areas that sustained TAI.

中文翻译：

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多尺度白质束嵌入式脑有限元模型预测外伤性弥漫性轴索损伤的位置。

有限元模型 (FEM) 越来越多地用于创伤性脑损伤 (TBI) 领域，以提供组织反应的估计并预测生物力学事件后维持 TBI 的概率。然而，FEM 研究主要侧重于预测 TBI 的缺失/存在，而不是估计损伤的位置。在这项研究中，我们创建了一个带有嵌入轴突束的猪脑的多尺度 FEM，以估计头部快速旋转后急性（≤6 小时）外伤性轴突损伤 (TAI) 的部位。我们检查了三个与轴突束变形相关的有限元 (FE) 衍生指标和三个基于脑组织变形的有限元衍生指标，用于预测急性 TAI 位置。在猪身上进行快速头部旋转，生成 TAI 神经病理学图并与 FEM 共定位。FEM 衍生的大脑/轴突变形的分布在空间上与急性 TAI 的位置相关。对于六个候选指标中的每一个，我们检查了不同伤害阈值的矩阵（th_x ) 和到实际 TAI 站点的距离 (d _s ) 以最大化两个优化标准的平均值。三个与轴突变形相关的 TAI 候选者预测了 2.5 毫米内的急性 TAI 位点，但没有成功的脑组织测量。最大轴突应变、最大轴突应变率以及轴突应变与应变率的最大乘积的最佳阈值范围分别为 0.08–0.14、40–90 和 2.0–7.5 s ^-1。这些阈值的上限导致更高的真阳性预测率。总之，这项研究证实了大轴突束变形发生在/接近维持 TAI 的区域的假设。