OP0001 [18F]Fdg PET in Giant-Cell Arteritis: A Prognostic Tool for Aortic Complications
Authors: H. de Boysson, E. Liozon, M. Lambert, J.-J. Parienti, J. Boutemy, K. Ly, P.-Y. Hatron, A. Manrique, B. Bienvenu
Journal: Annals of the Rheumatic Diseases (2014)

<h3>Background</h3> Extracranial involvement of large vessels in giant-cell arteritis (GCA) is probably underdiagnosed. Aortic complications (dilatation and dissection) are a prominent cause of death. [18]F-fluorodeoxyglucose positron-emission tomography ([18F]FDG-PET) is an imaging tool that can demonstrate the inflammation of large vessels. <h3>Objectives</h3> To assess the value of PET in the diagnosis, the extent of disease9s activity and the follow-up of patients with GCA. <h3>Methods</h3> Patients were enrolled if they satisfied two criteria: (1) diagnosis of GCA was established fulfilling the American College of Rheumatology criteria (including patients with two criteria and extra-temporal biopsy-proven giant-cell vasculitis); and (2) at least one PET had been performed, at diagnosis (before or in the first 10 days of corticosteroid treatment) or during the follow-up. Patients9 charts were retrospectively reviewed. Clinical symptoms were divided into cephalic and extra-cephalic manifestations. Positivity of PET was defined as a FDG vascular uptake superior to the liver on at least one of the eight following vascular segments: thoracic, abdominal aorta, subclavian, axillary, carotidian, iliac/femoral, and upper and lower limb arteries. Isolated uptakes from the iliac/femoral arteries were not considered as a positive PET. <h3>Results</h3> 133 patients were enrolled (88 women [66%], median age 70 [50–86]). GCA was biopsy-proven in 78 patients (59%), including 14 positive temporal-artery biopsies (TAB) in patients without any cephalic symptoms. PET was performed at diagnosis in 67 patients and during the follow-up in 66 patients. PET results were positive in 68 (51%) patients and a median of 4 [1–8] vascular areas were involved. The thoracic aorta was involved in 79% of cases. Patients with a positive PET had significantly more extra-cephalic manifestations (59% vs. 37%, <i>p</i>=0.001) and less cephalic symptoms (71% vs. 94%, <i>p</i>=0.0005) than patients with a negative PET. No difference was noted between the 2 groups regarding the TAB status, inflammatory parameters, or cardiovascular risk factors. With a median follow-up of 35 months [6–263], 76 (57%) patients relapsed, and PET results were not clinically useful in 24/26 patients in whom another PET was performed. Aortic dilatation occurred in 14 (11%) patients (of which, 11 [16%] had a positive PET, <i>p</i>=0.03) and aortic dissection in three patients with a positive PET (all with a known dilatation). In univariable analyses, occurrence of aortic complications was associated with the positivity of PET and the absence of cephalic manifestations (hazards ratio (HR) 3.96 [95% confidence interval 1.1–14.26] and 0.27 [95% CI 0.09–0.85]). <h3>Conclusions</h3> To the best of our knowledge, this is the most extensive study on the use of PET in GCA. Half of the assessed patients had an extra-cephalic involvement of GCA. Large-vessel involvement demonstrated on a PET is associated with a higher risk of aortic complications. <h3>Disclosure of Interest</h3> None declared <h3>DOI</h3> 10.1136/annrheumdis-2014-eular.1985