Background Chronic pain is now the number one reason for medical visits and a major driver of the opioid epidemic. Oftentimes, patients with chronic pain exhaust standard treatment options with little symptomatic relief due to our inability to precisely identify pain generators. 18F-FDG PET/MRI provides a highly sensitive method to identify sites of active inflammation. Our overarching goal is to determine whether 18F-FDG PET/MRI can improve outcomes in patients with challenging pain conditions.

Methods Twenty-two patients, whose source of chronic pain was unclear, were referred for 18F-FDG PET/MR imaging by their physicians. Potential pain generators were identified as increased FDG uptake on PET and/or T2 abnormalities on MRI. The patients were then followed to determine if their referring physicians altered their management based on the imaging findings.

Results All twenty-two cases had 18F-FDG PET/MRI results that directly impacted management after the results were reviewed with referring clinicians. Based on the findings, either a diagnostic injection at a new site was attempted/recommended or surgery was recommended. One patient had endured a proximal fifth metatarsal fracture and subsequently underwent surgical fixation. However, the patient suffered from chronic right lateral foot pain despite an adequate healing period, negative radiographic findings, and eventual removal of the bone screw. 18F-FDG PET/MRI revealed increased FDG uptake at the site of the previous fracture, suggesting fracture instability and chronic osteitis. Additionally, MRI showed an inflamed and swollen sural nerve entering an area of scarring near the fracture site. This patient has been referred for anesthetic block of the sural nerve and possible surgical correction of the bone inflammation. Another patient had lower back pain initially attributed to Bertolotti’s disease. However, 18F-FDG PET/MRI demonstrated increased FDG uptake in both sacroiliac joints consistent with sacroiliitis and a lack of uptake at the pseudo-articulation. Bilateral SI joint injections were performed with excellent symptomatic relief.

Conclusion Chronic pain is a debilitating condition affecting millions worldwide and is difficult to diagnose due to our inability to target pain generators. 18F-FDG PET/MRI has shown groundbreaking promise in identifying pain sources and in preliminarily altering clinical management, leading to improved quality of life for individuals suffering from chronic pain.