Using high frame-rate ultrasound and ¡1 sensitive motion tracking we previously showed that shear waves at the surface of and brains develop into shear shock waves deep inside the brain, with destructive local accelerations. However post-mortem tissue cannot develop injuries and has different viscoelastodynamic behavior from tissue. Here we present the ultrasonic measurement of the high-rate shear shock biomechanics in the porcine brain, and histological assessment of the resulting axonal pathology. A new biomechanical model of brain injury was developed consisting of a perforated mylar surface attached to the brain and vibrated using an electromechanical shaker. Using a custom sequence with 8 interleaved wide beam emissions, brain imaging and motion tracking were performed at 2900 images/s. Shear shock waves were observed for the first time wherein the shock acceleration was measured to be 2.6 times larger than the surface acceleration ( 95 vs. 36). Histopathology showed axonal damage in the impacted side of the brain from the brain surface, accompanied by a local shock-front acceleration of . This shows that axonal injury occurs deep in the brain even though the shear excitation was at the brain surface, and the acceleration measurements support the hypothesis that shear shock waves are responsible for deep traumatic brain injuries.

中文翻译：

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体内剪切冲击波损伤：高帧率超声观察和组织学评估

使用高帧率超声波和¡1敏感运动跟踪，我们之前表明，大脑表面的剪切波发展成大脑深处的剪切冲击波，具有破坏性的局部加速度。然而，死后组织不会产生损伤，并且具有与组织不同的粘弹动力学行为。在这里，我们介绍了猪脑中高速剪切冲击生物力学的超声波测量，以及由此产生的轴突病理学的组织学评估。开发了一种新的脑损伤生物力学模型，该模型由附着在大脑上的穿孔聚酯薄膜表面组成，并使用机电振动器进行振动。使用具有 8 个交错宽光束发射的自定义序列，以 2900 个图像/秒的速度执行大脑成像和运动跟踪。首次观测到剪切冲击波，其中测得的冲击加速度比表面加速度大2.6倍（95 vs. 36）。组织病理学显示大脑受影响侧的轴突损伤来自大脑表面，并伴有局部冲击波前加速度。这表明，即使剪切激励发生在大脑表面，轴突损伤也发生在大脑深处，并且加速度测量结果支持剪切冲击波导致深部创伤性脑损伤的假设。