Spectrally optimized, Spatially resolved Poro and Viscoelastic Brain MRE

描述(申请人提供)：我们已经建立了一种创新的脑磁共振弹性成像(MRE)方法，该方法基于对脑血管系统中血液脉动引起的内源性低频(~1赫兹)运动的编码，该运动通过多孔弹性力学模型重建，以产生三维(3D)、空间分辨率的机械和流体动力学特性图像。我们的多孔弹性磁共振成像(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，我们基于外部高频(50-100赫兹)激励的粘弹性磁流变(VMRE)方法也取得了很大进展，我们在幻影、动物和人类中进行的最新vMRE研究的初步数据也非常令人印象深刻，因为可以获得空间分辨的机械性能信息。事实上，我们有证据表明，vMRE和pMRE是互补的--即在外部激励的高频下，vMRE是选择的方法，在脑实质的粘性阻尼效应更占优势的地方，而在内部激励的低频下，pMRE是最好的选择，因为流体动力效应变得更加重要。我们在这个项目中的总体目标是统一和优化我们的pMRE和vMRE方法，以便在一系列模型和动物模型系统中跨感兴趣的频谱(~1-100赫兹)对它们进行评估，以确定它们提供更好、可比较和/或互补的图像和数据的条件。具体地说，我们将(1)开发一个统一的框架和平台，通过它我们将改进和优化我们的pMRE和vMRE图像重建方法，(2)使用致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)在三个参数和实验条件可控的大型动物模型上完成实验，在体内进行比较评估。已经有证据支持脑MRE的潜力，为临床识别和处理多种神经疾病提供信息。我们假设大脑MRE可以提供更多的东西-具体地说，3D、光谱优化的、空间分辨率的组织力学和流体动力学属性地图应该是标准-而不是到目前为止大部分报道的整个/局部大脑机械属性的平均值。与pMRE和vMRE一样，外部和内部脑刺激都有优点；因此，需要集中和持续地努力在可用频率范围内优化、评估和比较这些方法，以确定在选定的和主要的感兴趣条件下选择的方法。

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.