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

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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.