Use of PET/MR Imaging in Chronic Pain

Use of [18F]FDG PET/MRI in the Diagnosis of Pain Generators and/or Sites of Inflammation and to Monitor Treatment Effects in Patients With Chronic Pain

The investigators are studying the ability of PET/MR imaging (using the PET tracer [18F]FDG) to objectively identify and characterize pain generators in patients suffering from chronic pain.

The diagnosis and management of chronic and neuropathic pain syndromes remains a major clinical challenge, and this failure is partly attributed to our inability to identify the hypersensitive and inflammatory changes in the pain-sensing part of our nervous system that is thought to contribute to these syndromes. The lack of a specific, objective diagnostic test for chronic and neuropathic pain syndromes can result in a delay of diagnosis and suboptimal management decisions. This delay in diagnosis is quite unfortunate since the early diagnosis and treatment of a disease is attributed to the highest probability of remission in certain chronic pain syndromes. Additionally, identifying the correct source of pain is of paramount importance since the clinical course and therapeutic interventions are different depending on cause. Evidence in the literature points strongly toward an active inflammatory component in chronic pain. For example, soft tissue and bony inflammation is known to be an important pathophysiological mechanism for the symptoms of certain neuropathic pain syndromes. Similarly, individuals suffering from chronic sciatica or radiculopathy may suffer from a combination of inflammation and compression of lumbar or cervical spinal nerves. It is also established that inflammatory lesions have increased metabolism and energy requirements and, therefore, are more glucose-avid than normal tissues, showing increased uptake of radiolabeled glucose analogs, such as [18F]fluorodeoxyglucose ([18F]FDG). Correspondingly, [18F]FDG positron emission tomography-magnetic resonance imaging (PET/MRI) represent leading FDA-approved clinical imaging modalities to longitudinally study metabolic changes in the nervous system and non-neural tissues (e.g., muscle, blood vessels, joints, bone, scar tissue, etc.) in patients with chronic pain conditions. One of the goals of the study is to determine whether [18F]FDG PET/MRI can identify sources of inflammation with greater sensitivity, accuracy and objectivity than current diagnostic methods.

Positron emission tomography, Magnetic Resonance Imaging, PET/MRI, Fluorodeoxyglucose, FDG, Pain, Chronic Pain, Neuropathic Pain, Inflammatory Pain, Nociceptive Pain

Participants will be recruited based on established criteria for chronic pain. For the PET/MRI scan, the participants will be injected with 10 mCi±1 mCi of [18F]FTC-146 via the antecubital vein in a bolus injection. PET and MRI scans will be acquired simultaneously using a hybrid PET/MRI scanner. Following the scan, participants will be contacted to check for adverse drug events, and any events will be recorded in the case report. The biodistribution of radiotracer will be analyzed using regions of interest (ROI) marked on anatomical structures on magnetic resonance images and quantifying the signal in PET images within the same ROIs. Pharmacokinetic information will be derived using mathematical modeling. Data from chronic pain patients will be compared to historical data from asymptomatic controls.

We will use PET/MRI to establish the normal range of [18F]FDG uptake. (SUVmax) in various anatomic structures, such as the spinal cord, peripheral nerves, dorsal root ganglia, muscle, bones, joints, blood vessels, of asymptomatic subjects.

Inclusion Criteria: Age 18 years or older. Chronic pain lasting greater than 2 months. For example: Low back pain, sciatica, complex regional pain syndrome, peripheral nerve injury, fibromyalgia, neuropathy, osteoarthritis, cancer pain, persistent post-operative pain, and migraine. Provides informed consent On a typical day, pain level of at least 4/10 on a 0-10 Comparative Pain Scale Covid Vaccination status: Vaccinated or unvaccinated subjects who received a negative test result from the Covid test within 72 hours of the scan. Exclusion Criteria: MRI-incompatible Diabetes Pregnant or nursing Non-English speaker Claustrophobic

There is currently no plan to share the individual participant data with other researchers outside our group of researchers or referring physicians.

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