Advanced 7 Tesla imaging of the knee for root cause of Osteoarthritis

摘要： 最近FDA批准7T用于膝关节的临床成像，开启了这种超高场的可能性 磁共振成像平台将成为生物医学研究和患者管理中更加突出的工具。 传统上，肌肉骨骼(MSK)研究和诊断性成像都是在 1.5和3T的字段。虽然超高场(UHF)7T仪器和FDA的可用性越来越高 7T在头部和膝盖的临床应用获得批准，该系统的真正能力只有一小部分 被剥削。首先，只批准在单一传输模式配置下运行。AS 这样，临床医生不能利用可用的并行传输(PTX)功能来集成 用于解决B1+同质性和本地SAR管理的最先进的解决方案。即使可用， 不存在使用PTX功能的RF线圈和优化例程。第二，传统诊断法 用于评估膝关节的成像方法没有充分利用形态、成分和 在超高频下进行磁共振成像时可获得的功能数据。无论是传统的还是新型的成像方法 同样受益于7T信噪比的提高。提高的敏感度可以被用来 提供已知对诊断有实际和重大影响的更高分辨率的图像 膝盖的精确度。此外，某些方法在较低的场强下会受到太大的影响。 作为3T及以下常规成像的一部分，包括定量钠等技术 通过动脉自旋标记测量成像和血流灌注。在本提案中，我们重点介绍了 为实现7T膝关节成像的全部潜力而开发的工程、方法和方案 并提供一项关键的转化性研究，重点是这些方法对临床护理的影响。这 工作将通过完成四个具体目标来完成。目标1将专注于开发， 采用超高介电常数(UHDC)材料的PTX射频线圈集成和优化 提供高分辨率形态膝关节成像方法的RF管理策略，包括ZERO 回声时间成像。目标2将实施和优化定量的成分和功能方法 在7T时评估膝关节，包括T1Rho和动脉自旋标记(ASL)灌注法。目标3 将涉及使用uHDC材料开发和优化钠(23Na)膝部线圈 准确测定膝关节软骨中~(23)Na浓度的策略最后， 翻译目标4，将涉及一项试点研究，以探索开发的技术和 影响PatientCare的方法。这项提议中的技术发展将使膝关节成像技术在 7T，并有可能加快其临床应用。预计试点研究的结果将立即产生 和重要的影响，形成了未来评估效果的纵向前瞻性研究的基础 医疗治疗对临床结果的影响。

ABSTRACT: The recent FDA approval of 7T for clinical imaging of the knee, opens the possibility that this ultrahigh field MRI platform will become a more prominent tool in biomedical research and patient management. Musculoskeletal (MSK) research and diagnostic imaging have been traditionally performed at magnetic fields of 1.5 and 3T. While there is increasing availability of ultrahigh field (UHF) 7T instruments and FDA approval of 7T clinical use in the head and knee, only a fraction of the system’s true capability is being exploited. First, approval has only been given for operation in a single transmit mode configuration. As such, clinicians cannot take advantage of the available parallel transmit (pTx) functionality to integrate state-of-the-art solutions for tackling B1+ homogeneity and local SAR management. Even if available, the RF coils and optimization routines to use the pTx functionality do not exist. Second, traditional diagnostic imaging methods for evaluating the knee do not fully exploit the array of morphologic, compositional, and functional data available when performing MRI at UHF. Both the traditional and novel imaging approaches alike benefit from the increased signal-to-noise ratio at 7T. The increased sensitivity can be exploited to provide higher resolution images that are known to have a real and significant impact on diagnostic accuracy in the knee. Furthermore, certain methods are simply too compromised at lower field strengths to be obtained as part of routine imaging at 3T and below including techniques like quantitative sodium imaging and perfusion as measured through arterial spin labeling. In this proposal we focus on the engineering, methodological and protocol developments to realize the full potential of 7T knee imaging and provide a critical translational study focusing on the utility of the methods to impact clinical care. This work will be accomplished by completing four specific aims. Aim 1 will focus on the development, integration, and optimization of a pTx RF coil coil using ultrahigh dielectric constant (uHDC) material and RF management strategies to provide high-resolution morphological knee imaging methods including zero echo time imaging. Aim 2 will implement and optimizequantitative compositional and functional methods for evaluating the knee joint at 7T including T1rho andarterial spin labeling (ASL) perfusion methods. Aim 3 will involve the development and optimization of a sodium (23Na) knee coil using uHDC material and strategies for accurate quantification of 23Na concentration in the articular cartilage of the knee. Finally, the translational Aim 4, will involve a pilot study to explore the ability of the developed technologies and methods to impact patientcare. The technical developments in this proposal will advance knee imaging at 7T and likely accelerate its clinical adoption. The results of the pilot study are expected to have an immediate and important impact,by forming the basis of future longitudinal prospective studies evaluating the effects of medical treatmentson clinical outcome.