MICROSCOPIC MRI T2 ANISOTROPY IN ARTICULAR CARTILAGE

缺乏检测软骨退化的非侵入性标记物 妨碍了对发展的基本理解 骨关节炎(OA)以及早期诊断和干预 骨关节炎。与传统的磁共振成像(MRI)不同的是，MRI测量或 仅比较软骨图像强度、面积或体积、显微MRI (MuMRI)非常适合于关节的定量研究 软骨。MuMRI不仅可以产生水的定量图像 分布，而且还有反映分子水平的独特参数 显微分辨率的组织中的信息。 在最近一项使用自旋-自旋弛豫时间(T2)的MuMRI研究中，我们 在14µM像素分辨率下定量地证明：(1)存在 犬关节软骨独特的T2各向异性。我们的目标是利用 T2松弛作为一种敏感的、无创的MRI标志物 关节软骨的组织结构和分子相互作用。我们 提出一些具体目标(1)以确定关系 MUMRI T2各向异性与肿瘤组织学定位的关系 (2)研究T2纤维的异质性。 节理中不同承载区域的各向异性；(3)检测 软骨T2分布的局部性各向异性； 目的：确定软骨中的蛋白多糖成分在软骨中的作用。 T2各向异性；(5)比较正常软骨的T2特性 与自然损伤的软骨进行比较；以及(6)确定 加载过程中软骨的区域特异性特征。在……里面 结合起来，这六个目标将产生原本无法获得的新的 阐明各种生物物理、生化和生物的信息 这一重要生物材料在分子水平上的机理和性质 水平。 我们的方案在结合MuMRI的高分辨率特性方面是独一无二的， 定量T2测量和组织学信息。这个 MuMRI技术的完善是我们工作的最大力量。 我们现在可以在单独的组织学上检查组织特性 软骨中的非侵入性和显微分辨率的区域，因此 有助于理解并最终预防 关节炎。

A lack of non-invasive markers to detect cartilage degradation has prevented a fundamental understanding of the development of osteoarthritis (OA), as well as early diagnosis of and intervention in OA. Unlike convention Magnetic Resonance Imaging (MRI) that measures or compares only cartilage image intensity, area or volume, Microscopic MRI (muMRI) is well-suited for the quantitative study of articular cartilage. The muMRI can produce quantitative images not only of water distribution, but also of unique parameters reflecting molecular level information in the tissue at microscopic resolution. In a recent muMRI study using the spin-spin relaxation time (T2), we demonstrated quantitatively at 14muM pixel resolution that (1) there is a unique T2 anisotropy in canine articular cartilage. Our goal is to use T2 relaxation as a sensitive and non-invasive MRI marker to study the tissue structure and molecular interactions in articular cartilage. We propose a number of specific aims (1) to determine the relationship between the T2 anisotropy by muMRI and the histological orientation of the collagen fibrils; (2) to study the heterogeneity of the T2 anisotropy at different load-bearing areas in a joint; (3) to detect the localized anisotropies of the T2 distribution profile in cartilage; (4) to determine the role of the proteoglycan component of cartilage on the T2 anisotropy; (5) to compare the T2 characteristics of normal cartilage with that of naturally lesioned cartilage; and (6) to determine the zone-specific characteristics in cartilage during loading. In combination, these six aims will yield otherwise unavailable new information to elucidate various biophysical, biochemical and biological mechanisms and properties in this important biomaterial at the molecular level. Our proposal is unique in combining the high-resolution nature of muMRI, the quantitative T2 measurement, and histological information. The perfection of the muMRI techniques is the greatest strength of our work. We can now examine the tissue properties in individual histological zones in cartilage non-invasively and at microscopic resolution, thus contributing to the understanding, and ultimately, prevention of arthritic disease.