Insights Into Traumatic Brain Injury From MRI of Harmonic Brain Motion
Insights Into Traumatic Brain Injury From MRI of Harmonic Brain Motion
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DOI：
10.1177/1179069519840444
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发表时间：
2019-04-07
影响因子：
--
通讯作者：
Bayly, Philip, V
中科院分区：
文献类型：
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作者：
Okamoto, Ruth J.;Romano, Anthony J.;Bayly, Philip, V
人脑动态变形的测量。分析了由颅骨外部谐波振动引起的，以阐明轻度创伤性脑损伤（TBI）的机制。获得剪切波传播速度矢量场来说明头骨和坚硬的内膜在将运动传递到大脑中的作用。大脑和小脑之间的相对运动被量化，以评估连接结构的脆弱性。对整个大脑的机械变形进行量化，以研究应变和轴突拉伸的空间模式。当剪切波传播到大脑内部结构时，应变幅度通常会衰减：这种衰减在频率较高时更大。剪切波传播方向的分析表明，刚性膜（大脑镰和小脑幕）在颅骨运动过程中极大地影响大脑变形，因为它们是剪切波的起始和反射的场所。与两个结构的整体运动相比，小脑和大脑之间的相对运动很小。这表明这种相对运动在 TBI 力学中可能只发挥次要作用。脑沟基部附近的应变大小和轴突拉伸量与皮质其他区域的相似。未观察到灰白质边界处的局部应变集中。我们初步得出结论，在这些区域观察到的神经病理反应的差异可能是由于对机械变形的反应的异质性而不是变形本身的异质性。
Measurements of dynamic deformation of the human brain. induced by external harmonic vibration of the skull, were analyzed to illuminate the mechanics of mild traumatic brain injury (TBI). Shear wave propagation velocity vector fields were obtained to illustrate the role of the skull and stiff internal membranes in transmitting motion to the brain. Relative motion between the cerebrum and cerebellum was quantified to assess the vulnerability of connecting structures. Mechanical deformation was quantified throughout the brain to investigate spatial patterns of strain and axonal stretch. Strain magnitude was generally attenuated as shear waves propagated into interior structures of the brain: this attenuation was greater at higher frequencies. Analysis of shear wave propagation direction indicates that the stiff membranes (falx and tentorium) greatly affect brain deformation during imposed skull motion as they serve as sites for both initiation and reflection of shear waves. Relative motion between the cerebellum and cerebrum was small in comparison with the overall motion of both structures. which suggests that such relative motion might play only a minor role in TBI mechanics. Strain magnitudes and the amount of axonal stretch near the bases of sulci were similar to those in other areas of the cortex. and local strain concentrations at the gray-white matter boundary were not observed. We tentatively conclude that observed differences in neuropathological response in these areas might be due to heterogeneity in the response to mechanical deformation rather than heterogeneity of the deformation itself.