SAT0648 RELIABILITY OF MAGNETIC RESONANCE IMAGING (MRI)-SCORING OF THE METATARSOPHALANGEAL-JOINTS ACCORDING TO THE RHEUMATOID ARTHRITIS-MRI SCORE (RAMRIS)

Abstract

Background The Rheumatoid Arthritis Magnetic Resonance Imaging Score(RAMRIS) is validated for magnetic resonance imaging (MRI) of the hand. Its’ reliability when applied to metatarsophalangeal(MTP-1-5)-joints is unknown. Objectives To assess the interreader- and intrareader-reliability of status scores and the interreader-reliability of change scores applied to the MTP-joints for the following MRI-outcomes: bone marrow edema, synovitis, tenosynovitis and erosions. Methods Patients underwent 1.5T MRI of MTP(1-5)-joints. Two readers scored bone marrow edema(BME), synovitis, tenosynovitis and erosions. Interreader reliability was assessed of 441 consecutive early arthritis patients at baseline, the first 215 by two readers, the remaining 226 by two different readers. Additionally, baseline MRIs of 82 consecutive patients with arthralgia were scored by two readers, a random set of 40 patients by seven additional readers (nine readers in total). Intrareader reliability was determined on a random set of 15 early arthritis patients, scored twice by two readers. For change-scores, 30 early arthritis patients with baseline and 1-year follow-up MRI were scored by two readers. Intraclass correlation coefficients(ICCs), Bland-Altman(BA)-plots and smallest detectable change(SDC) were determined. Results Interreader mean scores and ICCs in early arthritis are presented in Table 1; ICCs were good to excellent (0.85-0.92) In arthralgia-patients mean scores were lower, ICCs were comparable (Table 1). Intrareader ICCs for MRI-features were good to excellent (0.84-0.98), but for erosions moderate for reader 1 (0.71 and excellent for reader 2 (0.92). Mean change scores and ICCs are presented in Table 2; ICCs were generally excellent (≥0.90), but moderate for erosions (0.77). SDCs were ≤1.0. BA-plots for status and change scores showed no systematic bias. Conclusion Status and change MRI-scores of BME, synovitis, tenosynovitis and erosions of MTP-joints can be assessed reliably by the RAMRIS. This is encouraging for the use of MRI of the MTP-joints in trials in early phases of RA. Disclosure of Interests Yousra Dakkak: None declared, Xanthe Matthijssen: None declared, Desiree van der Heijde Consultant for: AbbVie, Amgen, Astellas, AstraZeneca, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Daiichi, Eli-Lilly, Galapagos, Gilead, GlaxoSmithKline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, Union Chimique Belge, Monique Reijnierse Grant/research support from: Funding from the Dutch Arthritis Foundation. The funding source had no role in the design and conduct of the study., Annette van der Helm - van Mil Grant/research support from: The research leading to these results has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Starting grant, agreement No 714312) and from the Dutch Arthritis Foundation. The funding source had no role in the design and conduct of the study.