AB1179 VARIATION OF INTER-RATER RELIABILITY FOR BONE MARROW LESION SCORES IN DIFFERENT REGIONS OF THE KNEE: A STUDY USING KIMRISS

Background Semi-quantitative magnetic resonance imaging (MRI) scoring is more challenging in some anatomic regions than others. Bone marrow lesion (BML) an important feature and may be closely related to clinical outcomes arthritis The Knee Inflammation MRI Scoring System (KIMRISS) scores BML synovitis-effusion from fluid-sensitive sagittal [1] . Via web-based interface, readers place ready-made overlays onto scorable portions of each bone, divided into grid squares which are scored dichotomously (yes/no) for presence BML. total KIMRISS score, sums positive on all slices, has been previously shown have high inter-rater reliability both status change. Objectives We aimed evaluate patterns regional variation across the knee via elements. This granular analysis serves as a foundation further study relationship precise location outcomes. Methods Baseline 61 patients Osteoarthritis Initiative (OAI) dataset were by 8 trained using scoring. Total 28 overlay (14 femur, 10 tibia, 4 patella) calculated adding up slices. descriptive statistics interclass correlation coefficients (ICC) reader pairs, then combined any neighbouring locations with ICC <0.5 before recalculating ICC. Results 8-reader mean (SD) at (Table 1) showed that pair was very good (>=0.80) or (0.70-0.80) 17/28 (61%) (Figure 1). lowest ICCs occurred inferior patella [P4; ICC=0.52 (0.19)], small interior region femur [mean ICC=0.49 (0.26)], two most posterior tibia ICC=0.41 (0.26) 0.31 (0.33)]. Lower also found not immediately adjacent tibiofemoral joint (ICC range: 0.60-0.67) well non-articular 0.59-0.65). Combining tibial (T5+T55) slightly improved compared separate ICC= 0.40 (0.29)]. Conclusion Most individual reliability. Decreased certain due lower incidence anatomical features lead difficulty interpretation specific locations. reliability, such those increase if discrepancy arises assigning score same different between readers. demonstrated here support impact Reference [1]Jaremko JL, Jeffery D, Buller M , et al Preliminary validation grading bone lesions osteoarthritis knee: data RMD Open 2017; 3: e000355. doi: 10.1136/rmdopen-2016-000355 Figure 1. labels baseline MRIs (n=61). Table (colour coded according Fig 1.) Patella Femur Tibia Region Mean P1 2.0 (2.5) Trochlear FT1 1.8 (2.7) Subchondral T1 1.6 (2.8) P2 2.5 (2.6) FT2 0.6 (2.0) T2 (3.0) P3 1.9 (2.3) FT3 2.6 T3 (3.1) P4 (1.1) FT4 0.8 (2.1) T4 1.4 Weight-bearing FC1 1.3 (2.2) T5 0.5 (1.0) FC2 (1.9) Below T11 (1.7) FC3 T22 FC4 0.3 (1.4) T33 (1.8) FC5 (1.6) T44 (1.5) FC6 0.2 (0.8) T55 (0.6) Posterior FP1 0.4 (0.9) FP2 (0.7) FP3 FP4 0.1 (0.5) Acknowledgements: NIL. Disclosure Interests Stephanie Wichuk: None declared, Paul Bird Consultant of: AbbVie, Bristol Myers Squibb, Celgene, Janssen, MSD, Novartis, Pfizer, Roche, UCB, Iris Eshed: Robert G Lambert Calyx, CARE Arthritis, Image Analysis Group (IAG), Walter P Maksymowych Boehringer, Eli Lilly, Galapagos, Grant/research from: Andrew McReynolds: Susanne Juhl Pedersen Speakers bureau: Ulrich Weber: Joel Paschke: Jacob L Jaremko: declared.