(18)F-FDG PET/MRI can be used to identify injured peripheral nerves in a model of neuropathic pain

Abstract

We demonstrated increased (18)F-FDG uptake in injured peripheral nerves in a model of neuropathic pain using small-animal PET/MRI.

Methods: A neuropathic pain model in rats was created by spared-nerve injury of the left sciatic nerve. Sham-operated rats without nerve injury were used as a control. The presence of pain was confirmed by testing for allodynia. Sequential small-animal (18)F-FDG PET and MRI scans of the thighs were obtained and coregistered. Autoradiography was performed on harvested nerves and muscle.

Results: The group with spared-nerve injury showed the development of allodynia in the operated limb (P < 0.001). Increased (18)F-FDG uptake was observed on both PET/MRI (P < 0.001) and autoradiography (P < 0.005) in the operated nerve in this group. (18)F-FDG uptake in the nerves correlated well with allodynia (ρ = -0.59; P < 0.024).

Conclusion: Animals with neuropathic pain show increased (18)F-FDG uptake in the affected nerve. Small-animal PET/MRI can be effectively used to localize (18)F-FDG uptake in peripheral nerves.