Temporomandibular disorders (TMDs) represent the second most commonly occurring musculoskeletal condition resulting in pain and disability, combining orthopedic principles with biopsychosocial models of pain. The TMJ has complex anatomy comprised largely of fibrocartilaginous components that on MRI are characterized as short T2 tissues (intrinsic MR property). Clinical Imaging Problem and Background: Standard clinical MRI sequences portray these tissues as signal void (black), making them difficult to visually characterize and to quantitatively evaluate. We have implemented high resolution short TE sequences and developed a new 3D UTE technique that was designed to optimally characterize the TMJ tissues. We have also developed novel quantitative MR sequences that combine UTE technique (to allow signal acquisition from TMJ disc, fibrocartilage, condylar subchondral bone) with T2 and T1 rho applications. The UTE T2 prep sequence is a hybrid quantitative MR technique designed to accurately evaluate short T2 values (reflecting collagen orientation and integrity) in the 2 to 10 msec range (as in TMJ tissues determined by our preliminary studies). The UTE T1 rho sequence is a quantitative MR technique that was designed to evaluate proteoglycan integrity in short T2 tissues. Hypothesis: We hypothesize that our prospective, randomized study will show that our novel 3T short TE and UTE MRI techniques tailored for short T2 tissue evaluation of TMJ condylar fibrocartilage and disc, compared to existing techniques tailored for long T2 tissues, will 1) provide more accurate morphologic and structural data including bony changes when evaluated qualitatively in vitro, 2) serve as more sensitive biomarkers of biochemical and biomechanical alterations, as well as degeneration, when evaluated quantitatively in vitro, and 3) offer stronger qualitative and quantitative correlates to in vivo clinical assessment scores. We propose to address this through 3 aims. In the first, we will compare the accuracy of morphologic MR grading based on high resolution 2D short TE and newly developed 3D UTE techniques to those tailored for long T2 tissues. In the second, we will compare sensitivity of quantitative MR properties determined from UTE MRI techniques (short T2 and T1rho values) to those obtained from techniques tailored for long T2 tissues (long T2 and T1rho values) to biochemical and biomechanical alterations, as well as histopathology. In the third we will implement novel 3T UTE MRI high resolution morphologic, 3D UTE, and quantitative UTE MR sequences (2D T2*, UTE T2 Prep and UTE T1 rho) sequences in asymptomatic volunteers and symptomatic patients and correlate findings with a clinical assessment scoring system. Innovation: Our study is innovative in that it uses newly developed MR pulse sequences that propose both morphologic and biochemical evaluation of tissue, and presents new concepts regarding tailoring MRI parameters to specific tissues, and exploring quantitative MR techniques as a biomarker for tissue function.
Temporomandibular disorders are a major cause of pain and disability in the general population. We propose to use newly developed MRI sequences that will serve as biomarkers for morphologic, biochemical and biomechanical alteration of TMJ tissues.
