Quantitative 3D Diffusion and Relaxometry MRI of the Knee

描述（由申请人提供）：骨关节炎（OA）影响超过一半的人群，但治疗选择和对OA的理解仍然有限，部分原因是量化疾病进展和治疗反应的非侵入性技术有限。虽然已经提出了许多磁共振成像（MRI）方法来成像OA，但它们都至少有一个主要的局限性，从扫描时间长到特异性有限。我们提出了一种新的MRI技术，称为定量双回波稳态（qDESS）成像，同时提供整个膝关节的三维形态和功能成像，包括水扩散和快速松弛测量。该项目旨在充分开发qDESS，以便其可以广泛使用，然后评估软骨和软骨中定量扩散和松弛测量的价值，以检测早期和时间变化。我们的具体目标是（1）开发一种稳健的扫描序列和伴随的后处理方法，以在3T下10分钟扫描中获得表观扩散系数（ADC）、T2和T2* 的高分辨率3D图，（2）通过切除的人体样本成像验证该技术，将定量成像参数与生化参数进行比较，软骨和软骨中的组织学和机械度量，以确定对组织变性的敏感性，以及（3）验证qDESS检测在前交叉韧带（ACL）撕裂后处于发展OA风险的受试者的膝关节中随时间的变化的能力。这项工作的创新之处在于开发了一种临床可行的技术 它同时提供（1）可用于全膝评分和放射学评估的形态学图像和（2）软骨和半月板的定量参数，包括体积和厚度测量、T2和T2* 图和ADC图，以及（3）评估滑膜炎的非对比增强方法。该提案的意义在于提供一种广泛可用的、定量验证的10分钟成像方法，使研究和临床MRI检查中早期骨关节炎的全面常规研究成为可能。

DESCRIPTION (provided by applicant): Osteoarthritis (OA) affects over half the population at some point in their lives, yet treatment options and understanding of OA remain limited, in part due to limited availability of non-invasive techniques to quantify disease progression and responses to therapies. While numerous magnetic resonance imaging (MRI) methods have been proposed for imaging OA, they all have at least one major limitation, ranging from long scan times to limited specificity. We propose a new MRI technique called quantitative double-echo in steady-state (qDESS) imaging that simultaneously offers 3D morphologic and functional imaging of the entire knee, including water diffusion and rapid relaxometry measurements. This project aims to fully develop qDESS so that it may be widely used, then to assess the value of quantitative diffusion and relaxometry measures in cartilage and menisci to detect early and temporal changes. Our specific aims are (1) to develop a robust scanning sequence and accompanying post-processing methods to obtain high-resolution 3D maps of apparent diffusion coefficient (ADC), T2 and T2* in a 10-minute scan at 3T, (2) to validate this technique with imaging of excised human samples, comparing quantitative imaging parameters with biochemical, histological and mechanical metrics in cartilage and menisci to determine sensitivity to tissue degeneration, and (3) to validate the ability of qDESS to detect changes over time in the knees of subjects at risk of developing OA following anterior cruciate ligament (ACL) tears. The innovation of this work lies in the development of a clinically feasible technique that simultaneously offers (1) morphologic images that can potentially be used for whole-knee scoring and radiologic assessment and (2) quantitative parameters in both cartilage and meniscus including volume and thickness measurements, T2 and T2* maps and ADC maps, and (3) a non-contrast-enhanced method to assess synovitis. The significance of this proposal is to offer a widely available, quantitatively validated 10-minute imaging method that makes comprehensive routine study of early osteoarthritis feasible in both research and clinical MRI exams.