Sub-Voxel Tissue Characterization With In-Vivo MRI

项目摘要 磁共振成像（MRI）是一种具有独特信息的软组织成像模式，其对比度 对组织的无数物理、化学和功能特性敏感，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， 非均质的，并且因此表现出NMR信号，该信号是空间变化的 特色大多数MRI协议提供可以在空间上分辨的组织之间的对比，但是产生 很少或没有关于NMR信号变化的定量信息，其存在于较小的尺度上，即， 亚体素尺度。这种定量的亚体素信息是诱人的，因为它提供了组织的特异性 显微解剖学定量亚体素MRI组织定征的发展需要协调 在两个方面取得进展：1）将相关微观解剖特征与1H相关的定量模型 NMR信号特征，以及2）可以将这些特征转化为实际有效的定量MRI方法 亚体素组织模型的使用为研究人员和临床医生提供了广泛的实用性。 拟议的研究解决建模和方法开发，旨在开发实用的 以及用于白色物质和骨骼肌的显微解剖特征的定量成像生物标志物， 包括1）正常、发育和异常发育中的髓鞘体积分数和髓鞘厚度 白色物质，和2）肌纤维体积分数和大小，在存在炎症和纤维化的情况下。等 生物标志物具有通过提供定量和特异性的生物标志物来影响研究和临床诊断的潜力。 跟踪与异常白色物质发育相关的疾病变化的措施，例如 精神分裂症和自闭症，以及肌肉损伤和疾病，如肌肉营养不良。

PROJECT SUMMARY 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.