Positron emission tomography with computed tomography imaging of neuroinflammation in experimental autoimmune encephalomyelitis

2-[F-18]Fluoro-2-deoXy-D-glucose positron emission tomography ([F-18]FDG PET) detection of the up-regulated glycolysis associated with malignant transformation is a noninvasive imaging technique used extensively in cancer diagnosis. Although striking similarities exist in glucose transport and metabolism between tumor cells and activated immune cells, the potential use of [F-18]FDG PET for the diagnosis and evaluation of autoimmune disorders has not been systematically investigated. Here we ask whether [F-18]FDG PET in conjunction with computed tomography (CT) could be used to monitor a complex autoimmune disorder such as murine experimental autoimmune encephalomyelitis (EAE) and whether this approach is sensitive enough to evaluate therapeutic interventions. We found that (i) coregistration of metabolic (i.e., microPET) and high-resolution anatomical (i.e., CT) images allows serial quantification of glycolysis with [F-18]FDG in various spinal column segments; (ii) [F-18]FDG PET/CT can detect the increased glycolysis associated with paralysis-causing inflammatory infiltrates in the spinal cord; and (iii the [F-18]FDG measure of glycolysis in the spinal cord is sensitive to systemic immunosuppressive therapy. These results highlight the potential use of serial [F-18]FDG PET/CT imaging to monitor neuroinflammation in EAE and suggest that similar approaches could be applied to the diagnosis and evaluation of other autoimmune and inflammatory disorders in animal models and in humans.