AB0504 TOPOGRAPHY OF 18F-FDG PET/CT INFLAMMATORY SITES IN SPONDYLOARTHRITIS IN COMPARISON TO POLYMYALGIA RHEUMATICA AND TO PATIENTS WITHOUT INFLAMMATORY RHEUMATIC DISEASE

• Published in: Annals of the rheumatic diseases Vol. 80; no. Suppl 1; pp. 1279 - 1280
• Main Authors: Giraud, N., Sondag, M., Chouk, M., Verhoeven, F., Wendling, D., Prati, C.
• Format: Journal Article
• Language: English
• Published: 01.06.2021
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2021-eular.2444

Background: Spondyloarthritis (SpA) is a common inflammatory rheumatism, characterized by axial and/or peripheral enthesitis. The positron emission tomography (PET/CT) allows the detection of inflammation. Objectives: Our objective was to study the rhizomelic fixation with 18F-FDG (18-Fluorine deoxyglucose) PET/CT in SpA, compared to a Polymyalgia Rheumatica (PMR) group and to a control without rheumatological manifestations Methods: Monocentric and retrospective study, including patients who have benefited from PET/CT. 2 groups of patients, with SpA on the one hand, and PMR on the other hand, fulfilling standard diagnostic criteria. A third group of controls (CN) benefiting from PET/CT in the context of assessment of a neoplasia. The rhizomelic fixations were evaluated according to the average of semi-quantitative scores. This in different rhizomelic sites, articular (gleno-humeral, coxo-femoral) and extra-articular (sub acromial (BSAD), trochanteric bursitis). Results: 147 patients were included: 44 SpA, 50 PMR, and 53 CN. The rhizomelic fixations were significantly lower in SpA compared to PMR: on the pelvic girdle [0.31(0.7) vs 1.15(1.04), p=1.2*10-10], the scapular girdle [0.15(0.44) vs. 1.35(1.2), p=7.09*10-15], the hip joints [0.27(0.62) vs 1.16(1.16), p=1.6*10-5], glenohumeral joints [0.18(0.49) vs. 1.71(1.04), p=4.75*10-12], the trochanteric bursae [0.36(0.77) vs 1.14(0.91), p=3.54*10-6], BSADs [0.11(0.38) vs. 0.98(1.24),p=4.63*10-5], or overall rhizomelic fixation. [0.23(0.59) vs. 1.26(1.14), p= 4.47*10-24]. The fixation was also significantly lower for SpA compared to CN, in trochanters [0.36(0.77) vs 0.58(0.68),p=3.54*10-6], at the glenohumeral joints [0.18(0.49) vs 0.58(0.66),p=3.27*10-5], pelvic girdle [0.31(0.7) vs. 0.49(0.67),p=0.0028] and scapular girdle [0.15(0.44) vs. 0.41(0.66), p=7.09*10-15] and on the global overall rhizomelic fixation [0.23(0.59) vs. 0.49(0.67), p=1.22*10-6]. Conclusion: Our study is the first to study the rhizomelic fixations with 18f-FDG in SpA, compared to another rheumatism inflammatory and controls. We found a lower fixation in SpA compared to PMR, confirming the major and specific rhizomelic fixation of PMR. We found a lower fixing of SpA compared to CN, without anatomical, articular or extra-articular systematization. SpA seems to be a condition with low uptake on 18f-FDG PET/CT, particularly at the rhizomelic level, compared to PMR and controls. Disclosure of Interests: None declared.