Spectrally optimized, Spatially resolved Poro and Viscoelastic Brain MRE

描述（由申请人提供）：我们已经建立了一种脑磁共振弹性成像（MRE）的创新方法，该方法基于对通过脑血管系统的血液脉动产生的内源性低频（~1Hz）运动进行编码，该脑血管系统用多孔弹性力学模型重建，以产生三维（3D）、空间分辨的力学和流体动力学特性图像。我们的多孔弹性MRE（pMRE）方法已经在幻影，动物和人类中产生了有希望的初步数据。与此同时，我们已经大大提高了基于外部高频（50- 100 Hz）驱动的粘弹性MRE（vMRE）方法，并且由于可以获得空间分辨的机械性能信息，我们在幻影，动物和人类中的最新vMRE研究的初步数据也非常令人印象深刻。事实上，我们有证据表明，vMRE和pMRE是互补的-即，vMRE是在外部驱动的高频率，其中脑实质的粘性阻尼效应更占主导地位的方法的选择，而pMRE是在内在驱动的低频率，其中流体动力学流体效应变得更加重要的最佳选择。我们在本项目中的总体目标是统一和优化我们的pMRE和vMRE方法，以便在一系列体模和动物模型系统中在感兴趣的频谱（~1- 100 Hz）上对其进行评估，这将确定它们提供上级、可比和/或互补图像和数据的条件。具体而言，我们将（1）开发一个统一的框架和平台，通过该框架和平台，我们将推进和优化我们的pMRE和vMRE图像重建方法，（2）使用驱动和体模系统在感兴趣的频率范围内进行比较评估，以及（3）在三个大型动物模型中完成实验，这些动物模型具有可控参数和实验条件，在这些条件下将在体内进行比较评估。已有证据支持脑MRE为多种神经系统疾病的临床识别和管理提供信息的潜力。我们假设，大脑MRE有更多的提供-特别是，3D，光谱优化，空间分辨的组织机械和流体力学特性的地图应该是标准的-而不是整个/区域的大脑机械特性的平均值，主要是迄今为止报道。外部和内在的大脑驱动都有优点，pMRE和vMRE也是如此;因此，需要集中和持续的努力来优化，评估和比较这些方法在可用的频率范围内，以确定在选定的和普遍的条件下选择的方法。

DESCRIPTION (provided by applicant): We have established an innovative approach to brain magnetic resonance elastography (MRE) based on encoding of endogenous low frequency (~1Hz) motion resulting from blood pulsation through the cerebrovascular system that is reconstructed with a poroelastic mechanical model to produce three- dimensional (3D), spatially-resolved mechanical and hydrodynamical property images. Our poroelastic MRE (pMRE) methods have produced promising preliminary data in phantoms, animals, and humans. In parallel, we have advanced substantially our viscoelastic MRE (vMRE) methods based on external high frequency (50- 100Hz) actuation, and preliminary data from our latest vMRE studies in phantoms, animals and humans are also very impressive because of the spatially-resolved mechanical property information that can be obtained. Indeed, we have evidence to suggest that vMRE and pMRE are complementary - namely that vMRE is the method of choice at externally-actuated high frequencies where the viscous damping effects of brain parenchyma are more dominant, whereas pMRE is the best choice at intrinsically-actuated low frequencies where the hydrodynamic fluid effects become more important. Our overall objective in this project is to unify and optimize our pMRE and vMRE methods in order to evaluate them across the frequency spectrum of interest (~1-100Hz) in a series of phantom and animal model systems which will identify the conditions under which they provide superior, comparable and/or complementary images and data. Specifically, we will (1) develop a unified framework and platform through which we will advance and optimize our pMRE and vMRE image reconstruction methods, (2) use actuation and phantom systems for comparative evaluations across the frequency range of interest, and (3) complete experiments in three large animal models with controllable parameters and experimental conditions under which comparative evaluations will occur in vivo. Evidence already exists to support the potential of brain MRE to inform clinical identification and management of multiple neurological disorders. We hypothesize that brain MRE has much more to offer - specifically, that 3D, spectrally-optimized, spatially-resolved maps of tissue mechanical and hydrodynamical properties should be the standard - not the whole/regional brain mechanical property averages that have largely been reported to date. External and intrinsic brain actuation both have merit, as do pMRE and vMRE; hence, a focused and sustained effort to optimize, evaluate and compare these approaches across the available frequency range is needed to identify the methods of choice under selected and prevailing conditions of interest.