3T MRI OF THE TMJ USING SHORT AND ULTRASHORT ECHO TIME (UTE) TECHNIQUES

描述（由申请人提供）：颞下颌关节（TMJ）是一种具有解剖学和生物力学复杂性的关节，是三分之一人群疼痛和症状的原因。虽然MR已经彻底改变了TMJ的评估，但表征髁突纤维软骨和椎间盘已被证明具有挑战性。这部分是由于传统脉冲序列对这些主要具有短T2值（T1和T2值是所有组织固有的MR特性）的组织的检测不完整。利用新的超短回波时间（UTE）序列，我们现在可以评估这些组织，使我们能够定量评估组织以确定其T1和T2值。有了这些值，我们可以定制合适的MR序列，以提供最佳的组织特异性信号强度或对比度，并使用这些定量值作为结构和功能完整性的反映。我们的假设是，与标准临床序列相比，专门用于评估TMJ髁突纤维软骨和椎间盘短T2组织的3T MR序列：1)将证明对组织学确定的结构改变具有敏感性和特异性，2)将反映生物力学改变的模式，3)将为TMJ内部紊乱和退行性改变患者提供定量T2值和定性数据，这些数据与临床评估评分工具相关。我们的具体目标包括：1)使用3T UTE技术测量TMJ组织的T1和T2*值，以便在这些短T2组织中定制MR序列以获得最佳对比度和信号，并使该技术适用于临床环境。2)通过比较基于定性图像的分级和T2*定量与组织学和生物力学参考，比较定制MR序列和标准临床序列在检测结构或功能改变方面的性能。3)将这些技术应用于有症状的患者群体，并将MR成像结果与临床评估评分系统进行比较。这些技术将强调使用最先进的3T MR扫描仪，以及首次提供TMJ组织定量评估的新技术。将这些技术转化为临床成像，可以提供一种强大的、非侵入性的TMJ组织评估手段，能够检测到组织变性的全谱，这是了解疾病进展的关键工具。公共卫生相关性：颞下颌关节是一个解剖学和生物力学复杂的关节，是三分之一人口疼痛的原因。本研究将使用3T MR成像结合新的成像序列来提供TMJ组织的定量测量，这些测量将与结构和功能完整性相关，并将用于优化组织对比和信号的MR序列。这些技术将转化为患者群体，以产生优化的MR图像和定量数据，这些数据可以与临床评分系统相关联。

DESCRIPTION (provided by applicant): The temporomandibular joint (TMJ) is an articulation with anatomic and biomechanical complexity that is a cause of pain and symptoms in one third of the population. While MR has revolutionized TMJ evaluation, characterization of the condylar fibrocartilage and disc has proven challenging. This is partly due to the incomplete detection of these tissues with predominantly short T2 values (T1 and T2 values are MR properties intrinsic to all tissues) by conventional pulse sequences. With novel ultrashort echo time (UTE) sequences we can now assess these tissues, allowing us to quantitatively evaluate the tissues to ascertain their T1 and T2 values. With these values, we can tailor appropriate MR sequences to provide optimal tissue specific signal intensity or contrast, as well as using these quantitative values as a reflection of structural and functional integrity. Our hypothesis is that 3T MR sequences tailored for evaluation of short T2 tissues of the TMJ condylar fibrocartilage and disc, compared to standard clinical sequences: 1) will prove sensitive and specific for structural alterations determined by histology, 2) will reflect patterns of biomechanical alteration, and 3) will offer quantitative T2 values and qualitative data in patients with TMJ internal derangement and degenerative changes that correlate with clinical assessment scoring tools. Our specific aims include: 1) To use 3T UTE techniques to measure T1 and T2* values of the TMJ tissues for the purposes of tailoring MR sequences for optimal contrast and signal in these short T2 tissues and to adapt this technique for use in the clinical setting, 2) To compare the performance of tailored MR sequences and standard clinical sequences for detecting structural or functional alteration by comparing qualitative image based grading and T2* quantification with histologic and biomechanical references, and 3) To translate these techniques to a symptomatic patient population and compare MR imaging findings with a clinical assessment scoring system.These techniques will stress the use of a state of the art 3T MR scanner, and novel techniques that will offer a quantitative evaluation of the TMJ tissues for the first time. The translation of these techniques into clinical imaging may provide a robust, non-invasive means of TMJ tissue evaluation that has the ability to detect the full spectrum of tissue degeneration, a crucial tool for understanding disease progression. PUBLIC HEALTH RELEVANCE: The temporomandibular joint is an articulation with anatomic and biomechanical complexity that is a cause of pain in up to one third of the population. This study will use 3T MR imaging in conjunction with novel imaging sequences to provide quantitative measures of the TMJ tissues that will be correlated with structural and functional integrity and will be used to optimize MR sequences for tissue contrast and signal. These techniques will be translated to a patient population to produce optimized MR images and quantitative data that can be correlated with clinical scoring systems.