EXPLORER Total Body PET/CT Imaging for Myofascial Pain

Myofascial pain syndrome (MPS) is a prevalent and debilitating condition representing a significant societal burden. It is a chronic muscular pain disorder involving one muscle or groups of muscles, which is frequently accompanied by decreased range of motion, weakness, autonomic phenomena, depression, anxiety, sleep disturbance, and altered mental function. MPS affects up to 85% of patients with chronic pain and it is one of the most frequent reasons for referral to large pain clinics. The highest age-specific incidence rate is in the early 20's while prevalence increases with age until the sixth decade of life. This specific epidemiology of the disease creates a large economic burden on society due to not only health-care related expense but, especially, due to disabilities and work absenteeism.

Patients often receive treatment for myofascial pain, which are often neither standardized nor evidence-based. Treatment for myofascial pain consists of pharmacologic and nonpharmacologic interventions. Pharmacologic therapies include nonsteroidal anti-inflammatory drugs, muscle relaxants, benzodiazepines, and opioids. All these therapies have systemic physical side effects which can lead to severe chronic complications, especially when chronically prescribed. All of these are also known as being addictive or misused/overused. Non-pharmaceutical approaches ranging from non-invasive physical force-based manipulations to mini-invasive interventions such as acupuncture. These non-pharmacologic approaches are associated with minimal or negligible side effects and have been recently introduced into a conceptual model of integrative medicine.

There are no validated biomarkers for qualitative or quantitative assessment of MPS, which can be used to guide clinical management. It is crucial to have a reliable biomarker to assess therapy or intervention response. While many approaches have been attempted with several different techniques including MRI and US, there has not been a solid effort to assess a functional/molecular biomarker with PET/CT. Conventional PET/CT scanners are affected by low signal efficiency collection and low spatial resolution, which have made them unpractical to develop MPS biomarkers. However, the first Total Body PET/CT (TB-PET/CT) was successful in imaging the whole body simultaneously (field of view of 194 cm), with low injected activity doses (1/20 of the regular dose) and reduced acquisition times (less than 1 minute). The Investigators conducted several first-in-human studies using the TB-PET/CT system in participants with cancer, autoimmune arthritis, Covid-19, neurodegeneration and HIV. This included imaging the entire body down to a single nail of the finger. These strong data clearly address challenges of current PET/CT systems, such as their inability to assess the entire body in the same phase of radiotracer uptake, long scan times resulting from sequential acquisitions of the entire body that may not be well-tolerated by patients, significant ionizing radiation exposure in the context of monitoring chronic disease activity in a longitudinal setting, and limited PET spatial resolution for measuring radiotracer uptake in small lesions. Therefore, TB-PET/CT is poised to shift the paradigm in a range of research areas towards utilizing of advanced imaging technology. The PET radiotracer Fluorodeoxyglucose (18F-FDG) is a marker of glucose metabolism and is the mostly common radiotracer used in the PET imaging field. This radiotracer is FDA approved. 11C-Butanol is a marker for blood perfusion. This radiotracer is not FDA approved, and it will be used under an IND for this study. In summary, these observations support our overall scientific premise that total body PET/CT can be used in the assessment of myofascial tissue dysfunction using both FDG and 11C-Butanol.