Group-Wise Evaluation and Comparison of White Matter Fiber Strain and Maximum Principal Strain in Sports-Related Concussion
Group-Wise Evaluation and Comparison of White Matter Fiber Strain and Maximum Principal Strain in Sports-Related Concussion
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DOI：
10.1089/neu.2013.3268
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发表时间：
2015-04-01
影响因子：
4.2
通讯作者：
McAllister, Thomas W.
中科院分区：
文献类型：
--
作者：
Ji, Songbai;Zhao, Wei;McAllister, Thomas W.
运动相关脑震荡是美国的一个主要公共卫生问题，然而其生物力学机制仍不清楚。体外研究表明轴突伸长是一种潜在的损伤机制；然而，当前基于响应的损伤预测指标（例如，最大主应变[图形]）通常不考虑轴突方向。我们研究了白质（WM）纤维方向在应变估计中的重要性，并对11名临床诊断为脑震荡的运动员的纤维应变[图形]与[图形]进行了比较。基于达特茅斯头部损伤模型（DHIM）创建了几何精确、具有高质量网格的特定个体头部模型，该模型已成功验证（性能评定为“良好”到“优秀”）。对于使用一系列损伤阈值（0.09 - 0.28）估计暴露于高应变的白质区域，[图形]和[图形]在分布（迪氏系数为0.13 - 0.33）和范围（约5 - 10倍差异）上都存在显著差异，尤其是在较高阈值水平和较高旋转加速度幅值时。例如，使用[图形]和[图形]，在根据一项体内动物研究确定的0.18的最佳阈值之上，预测的白质分别平均为3.2%和29.8%，平均迪氏系数为0.14。具有高[图形]的白质区域分布与弥漫性轴索损伤中白质破坏的典型异质性模式一致，并且在最佳阈值下的组间范围与从另一项独立研究中发现的经历分数各向异性和平均弥散率显著纵向变化的白质体素百分比（分别为3.2%和3.44%）吻合良好。这些结果表明在未来的脑损伤研究中考虑白质微观结构各向异性的重要性。
Sports-related concussion is a major public health problem in the United States and yet its biomechanical mechanisms remain unclear. In vitro studies demonstrate axonal elongation as a potential injury mechanism; however, current response-based injury predictors (e.g., maximum principal strain,[GRAPHICS]) typically do not incorporate axonal orientations. We investigated the significance of white matter (WM) fiber orientation in strain estimation and compared fiber strain ([GRAPHICS]) with[GRAPHICS]for 11 athletes with a clinical diagnosis of concussion. Geometrically accurate subject-specific head models with high mesh quality were created based on the Dartmouth Head Injury Model (DHIM), which was successfully validated (performance categorized as "good" to "excellent"). For WM regions estimated to be exposed to high strains using a range of injury thresholds (0.09-0.28), substantial differences existed between[GRAPHICS]and[GRAPHICS]in both distribution (Dice coefficient of 0.13-0.33) and extent (similar to 5-10-fold differences), especially at higher threshold levels and higher rotational acceleration magnitudes. For example, an average of 3.2% vs. 29.8% of WM was predicted above an optimal threshold of 0.18 established from an in vivo animal study using[GRAPHICS]and[GRAPHICS], respectively, with an average Dice coefficient of 0.14. The distribution of WM regions with high[GRAPHICS]was consistent with typical heterogeneous patterns of WM disruptions in diffuse axonal injury, and the group-wise extent at the optimal threshold matched well with the percentage of WM voxels experiencing significant longitudinal changes of fractional anisotropy and mean diffusivity (3.2% and 3.44%, respectively) found from a separate independent study. These results suggest the significance of incorporating WM microstructural anisotropy in future brain injury studies.