Giant cell arteritis is classified among large-vessel vasculitis. Its first manifestation may be a febrile state with elevation in inflammation markers (ESR, CRP) and for examinations of such patients it is possible to use PET (PET/CT) scanning. Aim. To verify if high FDG uptake in the walls of large vessels is corresponding with giant cell arteritis. Method. Based on PET (25 pts) and PET/CT (14 pts) examinations, 39 patients with suspicion of large-vessel vasculitis formed a cohort in which were 30 males and 9 females aged 45–81 with a mean age of 64.9 and median of 65 years. For verifying, a direct proof using histologic examination of a vessel excision (4 pts) or an indirect one – a therapeutic test for ESR and CRP decreases
during corticotherapy in immunosuppressive doses (39 pts) were opted. FDG uptake was measured in 7 vessel areas with an area evaluated as positive when it surpassed an
uptake of the liver parenchyma. As a control group a sample of 100 patients free from vasculitis was used. For comparison, results from further imaging examinations were
used. Results. Giant cell arteritis was proved in 3 from 4 histologic examinations. By indirect testing, vasculitis in all 39 patients was confirmed. In patients with vasculitis before the
use of corticotherapy, positivity of at least 3 vessel areas was found, whereas in the control group positivity was observed in 0–2 vessel areas. Further imaging examinations
did not detect clear symptoms of vasculitis, it could be evaluated as abnormal. Conclusion. The finding of generalized high FDG uptake in large vessels in patients with symptoms of active inflammatory disease gave evidence for large-vessel vasculitis. The PET (PET/CT) examinations detected the disease in its early phase and also determined the extent thereof. Direct imaging of afflicted temporal vessels was success