18F-FDG PET/CT for post-cardiac-arrest brain injury: current evidence and future directions

Post-cardiac-arrest brain injury is a major cause of death and long-term neurological disability after cardiac arrest, yet current prognostic tools provide limited information on regional cerebral metabolism and functional recovery. Fluorine-18 fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography (18F-FDG PET and PET/CT) provide a molecular imaging approach for evaluating cerebral glucose metabolism after global ischemia-reperfusion injury. This narrative review summarizes the limited preclinical and clinical evidence on the use of 18F-FDG PET and PET/CT in post-cardiac-arrest brain injury, including animal models, small clinical cohorts, studies of disorders of consciousness, and investigations of neuroprotective interventions such as targeted temperature management. Published studies have documented global and regional abnormalities in cerebral glucose uptake; however, the use of these findings to assess injury severity, monitor treatment response, or predict prognosis remains hypothesis-generating. The evidence base is further limited by small sample sizes, heterogeneous imaging protocols, uncertain optimal timing, cost, radiation exposure, and limited feasibility in critically ill patients. Further prospective studies with standardized acquisition, quantification, and interpretation protocols are needed to determine whether 18F-FDG PET or PET/CT can be integrated into multimodal neuroprognostication and therapeutic monitoring after cardiac arrest.