Sub-Voxel Tissue Characterization With In-Vivo MRI

描述（由申请人提供）：磁共振成像（MRI）是一种具有对比度的独特信息软组织成像模式，对组织的无数物理、化学和功能特征敏感，但通常缺乏特异性。在与水质子（1H）核磁共振（NMR）相关的空间尺度上，组织是异质的，并且因此表现出作为空间变化特征的复杂总和的NMR信号。大多数MRI协议提供可以在空间上分辨的组织之间的对比度，但是产生很少或没有关于存在于较小尺度（即，亚体素尺度）上的NMR信号的变化的定量信息。这种定量的子体素信息是诱人的，因为它提供了组织微观解剖的特异性。定量亚体素MRI组织表征的开发需要在两个方面协调推进：1）将相关微观解剖特征与1H NMR信号特征相关联的定量模型，以及2）可以将这些亚体素组织模型的使用转化为研究人员和临床医生的广泛实用性的实用且有效的定量MRI方法。 提出的研究解决了建模和方法开发，旨在开发白色物质和骨骼肌的显微解剖特征的实用和定量成像生物标志物，包括1）正常、发育和异常发育的白色物质中的髓鞘体积分数和髓鞘厚度，以及2）在存在炎症和纤维化的情况下的肌纤维体积分数和尺寸。这样的生物标志物具有通过提供定量和特异性测量来跟踪与异常白色物质发育相关的病症（例如精神分裂症和自闭症）以及肌肉损伤和疾病（例如肌营养不良症）的变化而影响研究和临床诊断的潜力。 公共卫生相关性：MRI是一种广泛使用的诊断成像方式，能够相对无创地显示软组织。MRI中的对比度是由体内水分子彼此之间的许多复杂相互作用以及其局部环境的物理和化学特性引起的。这项研究计划旨在更好地将MRI对比度与神经组织和骨骼肌中的特定显微解剖特征联系起来。这项工作具有广泛的潜在影响MRI的诊断和预后能力的各种疾病和损伤。

DESCRIPTION (provided by applicant): Magnetic resonance imaging (MRI) is a uniquely informative soft tissue imaging modality with contrast that is sensitive to a myriad of physical, chemical, and functional characteristics of tissue but often lacks specificity. On the spatial scale relevant to water proton (1H) nuclear magnetic resonance (NMR), tissues are heterogeneous and, consequently, exhibit an NMR signal that is the complex summation of spatially varying characteristics. Most MRI protocols provide contrast between tissues that can be resolved spatially, but yield little or no quantitative information about the variation in NMR signal that exists on a smaller scale, that is, the sub-voxel scale. This quantitative sub-voxel information is alluring because it provides specificity to tissue micro-anatomy. Development of quantitative sub-voxel MRI tissue characterization requires coordinated advancement on two fronts: 1) quantitative models that relate relevant micro-anatomical characteristics to 1H NMR signal characteristics, and 2) practical and effective quantitative MRI methods that can translate these the use of sub-voxel tissue models to widespread utility for researchers and clinicians. The proposed studies address both modeling and method development with the aim to develop practical and quantitative imaging biomarkers for micro-anatomical characteristics of white matter and skeletal muscle, including 1) myelin volume fraction and myelin thickness in normal, developing, and abnormally developing white matter, and 2) myofiber volume fraction and size, in the presence of inflammation and fibrosis. Such biomarkers have the potential to impact research and clinical diagnostics by providing quantitative and specific measures to track changes in disorders associated with abnormal white matter development, such as Schizophrenia and Autism, as well muscle injuries and diseases such as Muscular Dystrophy. PUBLIC HEALTH RELEVANCE: MRI is a widespread diagnostic imaging modality capable of relatively non-invasive visualization of soft tissue. The contrast in MRI results from many complex interactions of water molecules in the body with each other and the physical and chemical characteristics of their local environments. This research program aims to better relate MRI contrast to specific micro-anatomical characteristics in neural tissue and skeletal muscle. This work has broad potential impact the diagnostic and prognostic capabilities of MRI for a wide array of diseases and injuries.