The role of 18F-fluorodeoxyglucose (FDG) positron emission tomography (18F-FDG PET) in the diagnosis of large vessel vasculitis (LVV) is well established. It permits us to assess the extent and the grade of vascular involvement and to rule out the other causes in clinical scenarios characterized by less specific symptoms. The advantages of 18F-FDG PET are far less clear in monitoring disease activity over time. Studies looking for the role of 18F-FDG PET as a potential biomarker had conflicting results and whether and when to repeat it during follow-up is based on clinical experience. A comprehensive assessment, including clinical, laboratory and morphological imaging is still required to monitor patients with large-vessel vasculitis over time. The aim of this review is to present more recent data about the utility of 18 F-FDG PET in the diagnosis and follow-up of LVV.