Foraminal [18F]FDG uptake on PET/MRI is associated with radicular symptoms and pain reduction after image-guided nerve root block

Motivation: The correlation of morphological findings on MRI and radiating low back pain (rLBP) is limited. Nerve irritation, visualized as increased glucose metabolism in FDG-PET-MRI, is a promising tool to identify symptomatic segments. Goal(s): To investigate the association of foraminal [18F]FDG uptake on PET/MRI and radiological pathology as well as patient outcomes. Approach: Patients with rLBP received both MRI and [18F]FDG PET of the lumbar spine; a subset of patients received image-guided nerve root block as part of their standard clinical care. Results: Nerve irritation, as visualized by [18F]FDG PET/MRI, is associated with foraminal stenosis and pain outcomes. Impact: Foraminal [18F]FDG uptake on PET/MRI as a surrogate marker of nerve irritation may improve the identification of pain generators on lumbar spine imaging in patients with radiating low back pain.