AB0620 IRON OVERLOAD IN SYNOVIUM DETECTED BY R2* MRI PREDICTS PROGRESSIVE BONE DESTRUCTION IN RHEUMATOID ARTHRITIS
Authors: S. Zhong, Y. Liu, C. Lu, B. Dong, W. Zhu, Y. Pan
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Iron overload has previously been determined to aggravate the pathologic process of rheumatoid arthritis (RA)(1). The current methods reported for iron quantification within the joint have been invasive, which greatly limits its clinical application. MRI (Magnetic Resonance Imaging) is highly sensitive to iron and has been widely used to detect local iron deposition in a great many diseases, such as liver diseases and Parkinson's Disease(2,3). However, there has not been an application of MRI on synovial iron evaluation in RA patients. <h3>Objectives:</h3> This study aimed to quantify the synovial iron in RA patients by MRI techniques and to reveal the role of iron overload in predicting RA progression. <h3>Methods:</h3> 42 RA patients with knee joint symptoms from the Third Affiliated Hospital of Sun-Yat sen University between July 2022 and December 2023 were recruited to undergo contrast-enhanced 3.0 T MRI scans. A total of three consecutive slices were used as the synovial region of interest (ROI). Synovium was manually defined using ITK-SNAP 3.5 Workstation on sagittal T1-weighted fat suppression sequence. Iron-related R2* values(S<sup>-1</sup>) in ROI were measured on R2* Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL-IQ) sequence. The RA MRI scoring system (OMERACT 2016 RAMRIS) was used to evaluate knee joint pathologies, including inflammation (synovitis, bone marrow edema) and structural impairment (joint space, bone erosion). Associations between R2*-quantified synovial iron and joint damage were analyzed by Spearman's rank correlation coefficients. Univariate and multivariate logistic regression models, were performed to calculate odds ratio (OR) to investigate the factors influencing bone erosion. <h3>Results:</h3> The results illustrated that synovial iron content detected by MRI in RA knee joint presented significantly positive association with bone erosion (OR 0.58, 95% CI: 0.33 to 0.76, P&lt;0.0001) and negative correlation with the joint space width (OR -0.36, 95% CI: -0.60 to -0.05, P&lt;0.05), but was irrelative with the serum iron level, disease activity score in 28 joints (DAS28), synovitis, nor bone marrow edema. Further multivariate logistic regression model analyses including five factors, namely synovial iron, synovial volume, DAS28-CRP, rheumatoid factor (RF), and anti-citrullinated protein antibodies (ACPA), were performed and established higher synovial iron as an independent risk factor for predicting bone destruction in RA (OR 0.16, 95% CI 0.093 to 0.233, P&lt;0.05). <h3>Conclusion:</h3> This study indicated excess iron in synovium as an independent risk factor for aggravated bone erosion in RA patients. MRI, as a non-invasive method to quantify arthritic iron, is highly valuable for widespread application in clinical practice. <h3>REFERENCES:</h3> [1] Liu Y, Luo X, Chen Y, Dang J, Zeng D, Guo X, et al. Heterogeneous ferroptosis susceptibility of macrophages caused by focal iron overload exacerbates rheumatoid arthritis. Redox Biology. 2024 Feb;69:103008. [2] Reeder SB, Yokoo T, França M, Hernando D, Alberich-Bayarri Á, Alústiza JM, et al. Quantification of Liver Iron Overload with MRI: Review and Guidelines from the ESGAR and SAR. Radiology. 2023 Apr 1;307(1):e221856. [3] Martínez M, Ariz M, Alvarez I, Castellanos G, Aguilar M, Hernández-Vara J, et al. Brainstem neuromelanin and iron MRI reveals a precise signature for idiopathic and LRRK2 Parkinson's disease. NPJ Parkinsons Dis. 2023 Apr 15;9(1):62. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>