In Vivo Measurement of Brain Biomechanics

描述（由申请人提供）：本研究的总体目标是开发和增强技术，以获得加速诱导的大脑变形，组织力学特性和脑-颅骨相互作用的体内数据。头脑生物力学的计算机模型为开发预防或减少创伤性脑损伤（TBI）的策略以及了解不同机械损伤的神经系统后遗症提供了巨大的潜力。然而，现有的模型仍然存在争议，因为计算机预测尚未在体内得到验证。验证的主要障碍是难以直接测量大脑变形。拟议的项目响应PA-04-006神经技术研究、开发和增强，通过开发技术来提高我们对主要神经健康问题：脑外伤的理解。该项目是由需求驱动的：技术进步将为开发和验证可靠的脑损伤计算机模型提供急需的脑生物力学数据。提出了两个具体目标：目标1：在人类和动物研究中使用MR标记，获得由头部加速度引起的组织变形（应变）的定量测量。在体内人类和猪大脑的受控加速过程中，将获得标记MR图像。大脑变形（应变），以及大脑和头骨之间的相对运动，将通过跟踪标记线的交叉点来测量。研究还将在原位和分离的猪脑中进行，以便与体内测量结果进行比较。目的2：结合组织各向异性扩散张量成像（DTI），通过MR弹性成像（MRE）获得脑组织力学参数的改进估计。脑组织的动态刚度可以无创地估计，在体内，从磁共振测量弹性波的传播。力学参数可能是各向异性的。通过DTI获得的各向异性数据将与MR弹性成像数据相结合，以实现对方向相关特性的稳健估计。技术转移：实验和数据处理程序的设计将最大限度地提高有限元（FE）建模研究界的可及性和实用性。该项目涉及来自华盛顿大学和宾夕法尼亚大学的多学科研究团队，他们在固体力学、生物力学、磁共振成像、磁共振仪器和创伤性脑损伤的有限元建模方面具有专业知识。

DESCRIPTION (provided by applicant): The overall objectives of this study are to develop and enhance technology to obtain in vivo data on acceleration-induced brain deformation, tissue mechanical properties, and brain-skull interaction. Computer models of head-brain biomechanics offer enormous potential for developing strategies to prevent or reduce traumatic brain injury (TBI), and for understanding the neurological sequelae of different mechanical insults. However existing models remain controversial because computer predictions have yet to be validated in vivo. The primary barrier to validation is the difficulty of direct measurement of brain deformation. The proposed project responds to PA-04-006 Neurotechnology Research, Development, and Enhancement by developing technology to improve our understanding of a major neurological health problem: TBI. The project is need-driven: the technological advances will provide much-needed data on brain biomechanics for the development and validation of reliable computer models of brain injury. Two Specific Aims are proposed: Aim 1: Obtain quantitative measurements of tissue deformation (strain) induced by head acceleration, using MR tagging in human and animal studies. Tagged MR images will be obtained during controlled accelerations of the in vivo human and porcine brains. Brain deformation (strain), as well as relative motion between the brain and skull, will be measured by tracking intersections of tag lines. Studies will also be performed in the in situ and isolated porcine brain for comparison to in vivo measurements. Aim 2: Obtain improved estimates of brain tissue mechanical parameters from MR elastography (MRE), combined with diffusion tensor imaging (DTI) of tissue anisotropy. The dynamic stiffness of brain tissue can be estimated non-invasively, in vivo, from MR measurement of elastic wave propagation. Mechanical parameters may be anisotropic. Anisotropy data obtained via DTI will be combined with MR elastography data to enable robust estimation of direction-dependent properties. Technology transfer: Experiments and data processing procedures will be designed to maximize accessibility and usefulness to the finite element (FE) modeling research community. The project involves a multi- disciplinary research team from Washington University and the University of Pennsylvania with expertise in solid mechanics, biomechanics, MR imaging, MR instrumentation, and FE modeling of TBI.