AB1353 VESSEL AFFECTION AND THE INFLUENCE OF GLUCOCORTICOIDS ON 18F-FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY IN GIANT CELL ARTERITIS

Abstract

Background: 18F-fuorodeoxyglucose positron emission tomography/computed tomography (PET/CT) represents one of the standard imaging modalities in the detection of giant cell arteritis (GCA). Detailed data regarding the vessel involvement in GCA are not available. Objectives: The aim of this study was to quantify arterial vessel involvement at the onset of GCA by 18F-FDG PET/CT and to verify the influence of glucocorti-coid treatment on the diagnostic performance of 18F-FDG PET/CT. Methods: This study included 60 patients (44 women and 16 men, mean age 72.8 ± 8.8 years) at the onset of GCA. All patients received a PET/CT. 44 patients were glucocorticoid naïve. 16 patient were treated with glucocorticoid (prednisone median dose 60 mg) 3.5 ± 4.4 days before the 18F-FDG PET/CT was performed. All 18F-FDG PET/CT scans were scored regarding the active infammation of the large arteries. Results: The most affected arteries were the aorta ascendens (72 %), followed by truncus brachiocephalicus (62 %), acrus aortae (60 %), aorta descendens (60 %), left and right arteria sublcavia (60 % and 58 %). The aorta and their outgoing arteries presented an involvement in 39 GCA patients (89 %). A singular affection of the aorta was shown in 9 patients (20 %). glucocorticoid naïve patients (89 %) showed affected arteries more frequently than glucocorticoid treated patients (38 %). Conclusion: The study showed that the thoracic aorta (in particular aorta ascen-dens) is the most involved vascular segment in GCA. The use of glucocorticoids was associated with a marked decrease of vascular infammation. Consequently, the imaging of the thoracic aorta should be included in the diagnostic procedure of GCA. 18F-FDG PET/CT should be performed without glucocorticoid treatment, if the clinical situation allowed this proceeding.