Sigma-1 receptor changes in chronic knee pain using PET/MRI: Preliminary results of fifteen patients

Motivation: Diagnosis of chronic knee pain remains a challenge with conventional diagnostic methods leading to unsatisfactory treatment in a large group of patients. Goal(s): To investigate the use of sigma-1 receptor (S1R) radioligand, [18F] FTC-146 in conjunction with positron emission tomography/magnetic resonance imaging (PET/MRI) for identifying the pain generator in chronic knee pain. Approach: Comparison of [18F] FTC-146 PET-MRI imaging findings in patients with unresolved chronic knee pain to healthy volunteers. Results: All 15 patients showed statistically significant increased uptake of S1R compared to healthy control subjects in a variety of locations. At sites of abnormal PET uptake, MRI often did not demonstrate abnormalities. Impact: Future clinical implementation of S1R-PET/MR can potentially help reveal previously unidentified pain generator in patients with chronic knee pain that have exhausted standard clinical care leading to better-targeted treatment.