Ultrashort TE MR Imaging of Femorotibial Cartilage

这项研究的一般目的是建立、验证并转化为临床方案，即磁共振成像 生物标志物，非侵入性地反映半月板之间的结构、功能和适应性关系， 以结构、组织学和生物力学参考标准为基础的软骨和软骨下骨。这 建议结合我们过去软骨和半月板研究的经验来发展一个统一的理论，即 半月板骨软骨单位(M-OCU)。这一理论强调的是 半月板、软骨、软骨下骨和骨髓。它是由结构和机械支撑的 胫骨半月板覆盖和未覆盖骨软骨面的关系以及 膝骨性关节炎的病理表型。开发一种允许非侵入性的单一研究方案 评估M-OCU的组成部分将有助于了解适应的程度和类型 发生在半月板损伤患者的这些组织中，改变了机械轴的设置。整体而言 假说是，完整的M-OCU保留了膝关节中正常的机械轴，进一步说， 半月板损伤的模式(视力、位置、特征)将预测下半月板的反应 骨软骨表面(适应性反应与失败)。提出了四个具体目标：1)身体 膝关节，我们将确定高分辨率3D Cube MR是否测量软骨下骨和松质骨 可作为组织结构和生物力学功能的生物标志物，用于表征组织的结构 以Micro CT为参照标准的软骨下(SC)骨板和SC松质骨，2)身体标本 膝盖，将决定骨髓的磁共振测量是否可以作为骨髓成分的生物标志物，以及 结合骨结构，提高对周围骨小梁生物力学功能的预测 骨，3)评估M-OCU(半月板、软骨、SC骨板、SC小梁骨和骨髓) 使用具有组织学、成像和生物力学参考的形态和定量磁共振序列 标准，以及4)将具有新的承载技术的M-OCU的MR成像评估转换为2 半月板修复治疗前后随时间变化的队列特征适应程度和模式 改建。目标1和目标2将建立磁共振技术的敏感度，通过新的硬件和 软件优化，对SC接骨板和SC松质骨的结构和功能进行优化。目标3将是一个 翻译目的：对正常膝关节和病理膝关节的M-OCU进行全关节MR分析。 目标4将把所有开发的技术应用于半月板缺陷患者队列，其中一组接受传统的 半月板切除与另一种半月板保留治疗的比较，后者被认为是为了更好地保存 机械轴，导致M-OCU的逐渐适应，并获得更好的临床效果。

The general purpose of this study is to establish, validate and translate to clinical protocol, MR imaging biomarkers that non-invasively reflect structure, function, and adaptive relationships between meniscus, cartilage and subchondral bone based upon structural, histologic, and biomechanical reference standards. This proposal incorporates our experience from past cartilage and meniscus research to develop a unified theory, that of the meniscal osteochondral unit (M-OCU). This theory emphasizes the dynamic relationship between meniscus, cartilage, subchondral bone and bone marrow. It is supported by structural and mechanical relationships in the meniscus covered and uncovered osteochondral surfaces of the tibia, as well as by pathologic phenotypes in knee OA. The development of a single study protocol that allows non-invasive evaluation of the components of the M-OCU will facilitate understanding the degree and type of adaptation that occurs in these tissues in the setting of an altered mechanical axis in meniscus-injured patients. The overall hypothesis is that the intact M-OCU preserves a normal mechanical axis in the knee, and further that the pattern of meniscal failure (acuity, location, character) will predict the response of the subjacent osteochondral surface (adaptive response versus failure). Four specific aims are proposed: 1) cadaveric knees, we will determine if high resolution 3D Cube MR measures of the subchondral bone and trabecular bone can serve as biomarkers for structure and biomechanical function of tissue, for characterizing the structures of the subchondral (SC) bone plate and SC trabecular bone using micro CT as a reference standard, 2) cadaveric knees, will determine if MR measures of bone marrow can serve as biomarkers for marrow composition, and together with bone structure, improve the prediction of biomechanical function of the surrounding trabecular bone, 3) to evaluate the M-OCU (meniscus, cartilage, SC bone plate, SC trabecular bone, and bone marrow) using morphologic and quantitative MR sequences with histologic, imaging, and biomechanical reference standards, and 4) to translate MR imaging evaluation of the M-OCU with a novel load-bearing technique, to 2 meniscal repair cohorts pre- and post-treatment over time to characterize degree and patterns of adaptive remodeling. Aims 1 and 2 will establish sensitivity of MR techniques, magnified by novel hardware and software optimization, to structure and function of SC bone plate and SC trabecular bone. Aim 3 will be a translational aim, to perform whole-joint MR analysis of M-OCU in normal vs. pathologic knees of cadavers. Aim 4 will apply all of the developed techniques to meniscus-deficient patient cohorts, one receiving traditional meniscectomy vs. another receiving meniscus-conserving treatments, which is hypothesized to better preserve mechanical axis, lead to gradual adaptation of M-OCU, and better clinical outcome.