Zero Echo Time Imaging of Knee Joint

项目总结 人类膝关节由许多不同的组织组成，包括关节软骨、钙化软骨、 半月板、韧带、肌腱和骨骼对关节的健康都很重要。最新研究 这表明骨关节炎不仅是透明软骨的疾病，而且是整个关节的疾病。几个 研究人员已经证明，T1ρ驰豫时间对蛋白多糖(PG)含量更敏感 软骨T2弛豫时间对胶原的取向、网状结构的完整性和 水合作用。短T1ρ半月板、钙化软骨、肌腱和韧带是关节不可分割的部分 这些组织中的生物力学和异常可能影响关节退变和骨性关节炎的发病。因此， 定量评估这些组织的松弛时间可能为早期诊断提供敏感的生化标志物。 OA诊断和疾病进展。然而，常规的T1ρ-MRI序列(例如，GRE和FSE 读数)在检测半固态短T1ρ组织或组织的早期大分子变化方面的价值有限 半月板、韧带和肌腱等组成部分。大部分膝关节结构，包括半月板， 韧带和肌腱都有主要的短(结合/限制水)与胶原和/或 蛋白质多聚糖)和少量长的(与大分子有关的较少限制/自由水)成分。 因此，非常需要可靠、无创、省时、基于中兴通讯的双指数3D-T1ρ 定量评价膝关节半固体结构的成像序列 具有短、长松弛成分的细胞外基质的早期生化变化及其意义 相应的分数。 此R21提案的首要目标是开发、优化和转换基于中兴通讯(Petra)的 双指数3D-T1ρ成像脉冲序列用于改进的形态和 膝关节(半月板、韧带和膝关节)半固态短T1ρ结构的生化特征 在采用多线圈压缩传感(CS)的标准临床3T扫描仪上。

PROJECT SUMMARY Human knee joints are composed of many different tissues including articular cartilage, calcified cartilage, menisci, ligaments, tendons and bone all of which are important for the health of the joint. Recent research suggests that osteoarthritis (OA) is not just a disease of hyaline cartilage, but rather of the entire joint. Several researchers have demonstrated that the T1ρ relaxation time is more sensitive to proteoglycan (PG) content of the cartilage, while T2 relaxation time is more sensitive to collagen orientation, integrity of network and hydration. The short T1ρ menisci, calcified cartilage, tendons, and ligaments are integral part of joint biomechanics and abnormalities in these tissues may impact joint degeneration and onset of OA. Therefore, quantitative evaluation of relaxation times in these tissues may provide sensitive biochemical markers for early OA diagnosis, and disease progression. However, conventional T1ρ-MRI sequences (e.g., GRE and FSE readouts) are limited value in detecting early macromolecular changes in semi-solid short T1ρ tissues or tissue components such as menisci, ligaments and tendons. Most of the knee joint structures, including menisci, ligaments and tendons have both dominant short (bound/restricted water associated with collagen and/or proteoglycans) and minor long (less restricted/free water associated with macromolecules) components. Therefore, there is a significant need for reliable, non-invasive, time efficient, ZTE-based biexponential 3D-T1ρ imaging sequence for quantitative assessment of semi-solid structures in the knee joint that could detect the early biochemical changes in extracellular matrix (ECM) with short and long relaxation components and their corresponding fractions. The overarching goal of this R21 proposal is to develop, optimize, and translate ZTE (PETRA)-based biexponential 3D-T1ρ imaging pulse sequence for improved quantitative assessment of morphological and biochemical characterization of semi-solid short T1ρ structures in the knee joint (menisci, ligaments and tendons) on a standard clinical 3T scanner employing multicoil compressed sensing (CS).