Traumatic brain injury such as that developed as a consequence of blast is a complex injury with a broad range of symptoms and disabilities. Computational models of brain biomechanics hold promise for illuminating the mechanics of traumatic brain injury and for developing preventive devices. However, reliable material parameters are needed for models to be predictive. Unfortunately, the properties of human brain tissue are difficult to measure, and the bulk modulus of brain tissue in particular is not well characterized. Thus, a wide range of bulk modulus values are used in computational models of brain biomechanics, spanning up to three orders of magnitude in the differences between values. However, the sensitivity of these variations on computational predictions is not known. In this work, we study the sensitivity of a 3D computational human head model to various bulk modulus values. A subject-specific human head model was constructed from T1-weighted MRI images at 2-$$\hbox {mm}^{3}$$mm3 voxel resolution. Diffusion tensor imaging provided data on spatial distribution and orientation of axonal fiber bundles for modeling white matter anisotropy. Non-injurious, full-field brain deformations in a human volunteer were used to assess the simulated predictions. The comparison suggests that a bulk modulus value on the order of GPa gives the best agreement with experimentally measured in vivo deformations in the human brain. Further, simulations of injurious loading suggest that bulk modulus values on the order of GPa provide the closest match with the clinical findings in terms of predicated injured regions and extent of injury.

中文翻译：

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体积模量对旋转加速度下大脑变形的影响

外伤性脑损伤，例如由爆炸引起的脑损伤是一种复杂的损伤，具有广泛的症状和残疾。脑生物力学的计算模型有望阐明创伤性脑损伤的机制和开发预防装置。但是，模型需要可靠的材料参数才能预测。不幸的是，人类脑组织的特性很难测量，尤其是脑组织的体积模量没有很好地表征。因此，脑生物力学的计算模型中使用了广泛的体积模量值，值之间的差异跨越了三个数量级。然而，这些变化对计算预测的敏感性尚不清楚。在这项工作中，我们研究了 3D 计算人体头部模型对各种体积模量值的敏感性。特定主题的人体头部模型是从 2-$$\hbox {mm}^{3}$$mm3 体素分辨率的 T1 加权 MRI 图像构建的。扩散张量成像提供了用于模拟白质各向异性的轴突纤维束空间分布和方向的数据。人类志愿者的非伤害性全场脑变形被用于评估模拟预测。比较表明，GPa 量级的体积模量值与实验测量的人脑体内变形的最佳一致性。此外，损伤载荷的模拟表明，GPa 数量级的体积模量值在预测的损伤区域和损伤程度方面与临床发现最接近。