基于 DTI 纤维追踪和有限元力学模型的脑损伤轴突纤维损伤研究

李娜 [1], 李江红 [2]
[1] 中南大学湘雅三医院,长沙,湖南,中国
[2] 中车集团南车研究所,株洲,湖南,中国
Published in 2015

研究头部损伤机理是对运动撞击中脑损伤进行预测的有效手段。数学模型是分析损伤实验数据、预测人员碰撞损伤程度的唯一方法,但现有的头部损伤有限元模型基于尸体实验数据,且忽略脑组织结构的各向异性。本项目旨在提出并实现一种以损伤生物力学为基础、结合磁共振扫描 DTI 的轴突走向信息的有限元力学模型。提取脑外伤前的弥散张量成像信息,实现深入到轴突水平有限元力学模型的建立,在有限元模拟中采用非线性超弹性力学模型,并植入 NSGAII 最优化方法对有限元模型的材料参数进行优化,从而提高模型的稳定性和计算精度;将计算预测结果与损伤后 DTI 的 FA 值所表现的轴突断裂情况进行验证, 探索活体环境下碰撞损伤中脑轴突的损伤性变化,从而获得脑外伤损伤程度与力学因素之间的关系,为脑外伤损伤程度的预测和脑外伤损伤标准的校正提供精确完整的信息。本项目的研究成果将在汽车碰撞的乘员防护设计上有重要的理论指导价值。

Traumatic brain injury (TBI) is the most primary cause of accident death in the world, and study of head injury mechanism is the most effective method to protect TBI. The finite element modeling (FEM) is the only method of analysis injury case data and predict injury Severity, while the available head injury FEMs are based on the cadaver experiment data, more importantly. These models ignored the anisotropy of brain tissue, particularly the axon fiber orientation. This project attempt to provide a new FEM combined with diffusion tensor image (DTI) to present the detailed axon geometry and axon injury level. The model will utilize the non-linear hyperelastic material model to simulate the brain tissue to improve the stability and accuracy of model. The NSGA-II algorithm will be utilized to optimize the material parameter. To investigate the injury mechanism of axon, explore the relevance between the external force and axon injury level. The validation will utilize the FA value of DTI after crash experiment. The prediction of FE modeling will be the definite axon injury. The research achievement will be a important theoretical value in designing new vehicle safety procedures to protect the drivers.

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