PROJECT SUMMARY/ ABSTRACT Myofascial pain syndrome (MPS) is a common public health problem. Knowledge of MPS injury mechanisms and treatment of this condition is currently limited by a lack of objective assessment tools. Efforts to better understand the origin and pathology of MPS have increasingly focused on impairments involving myofascial connective tissue and the function of fascial interfaces. Studies using ultrasound imaging technology to evaluate the function at sliding myofascial interfaces have provided insights into the underlying mechanisms of the syndrome. Researchers suggest that alterations in the viscoelastic properties of fascial structures may contribute to the MPS etiology. This may be perceived by patients as an increase in fascial stiffness and pain with restricted motion. However, major knowledge gaps remain in the understanding of myofascial biomechanics and how changes in these structures contribute to myofascial pain. Development of technology capable of providing biomarkers that quantitatively characterize the viscoelastic properties of myofascial tissue and the state of adhesion at interfaces would address these gaps and contribute to the assessment of therapeutic modalities. Currently, a noninvasive tool for quantifying fascia mechanical properties is very limited. Our goals are to (1) develop an MRE-based imaging technique for quantifying the mechanical properties of myofascial tissue and (2) establish new quantitative biomarkers for assessing impaired myofascial tissue and treatment efficacy. In Aim 1 (R61 phase), we will build an MRE-based framework to integrate multiple driving systems inducing desired shear motion in the lower back, upper and lower legs, respectively; an advanced pulse sequence to measure the corresponding full-volume dynamic 4D muscle displacement fields; and a post-processing approach to assess resultant mechanical parameters of the myofascial interface in those regions in vivo. This will create a foundation to characterize the myofascial interface mobility, stiffness, viscosity, and loading sensitivity. In Aim 2 (R61 phase), we will evaluate the repeatability and reproducibility of the MRE-assessed fascia mechanical properties in healthy volunteers using a test-retest strategy. A pilot clinical study will also be performed to evaluate and compare MRE-assessed fascia mechanical properties in age-/sex-matched normal and patients with conditions in the MPS spectrum. The transition milestone we are looking for is imaging biomarker(s) that demonstrate a statistically significant (p < 0.05) group difference. In Aim 3 (R33 phase), we will assess the abilities of the quantitative biomarker(s) developed in the R61 phase to monitor treatment responses to a physical force-based manipulation treatment (Tuina) and predict outcomes in a longitudinal study. Taken together, these aims will provide innovative methods and unique datasets for studying myofascial biomechanics, novel imaging biomarkers to distinguish healthy versus abnormal myofascial tissue and interfaces, and new imaging biomarkers to aid clinicians in developing effective approaches to myofascial pain, and helping to address one of the most important conditions that has led to overuse of opioid analgesics.

PROJECT NARRATIVE We will develop a magnetic resonance elastography (MRE) based technique to quantitatively assess the functional status of myofascial interfaces, reflected by fascial plane mobility, stiffness, and viscosity. This project’s successful completion will provide new quantitative imaging biomarkers for assessing the impaired myofascial tissue and evaluating treatment efficacy for myofascial pain syndrome.