LAUSR

Background Fluorescence Optical Imaging (FOI) is an imaging technique demonstrating indocyanine (ICG)-enhanced microcirculation in wrist and finger joints, as a sign of inflammation. A reliable scoring method is essential in the assessment of these images. Objectives To assess inter-reader reliability of three FOI scoring methods from Berlin, Stockholm, and Copenhagen, and to compare the amount of enhancement in joint groups of both hands in patients with erosive hand osteoarthritis (OA) and rheumatoid arthritis (RA). Methods Patients with erosive hand OA (n=13) and with RA (n=13) underwent FOI of both hands. Five readers blinded for clinical diagnoses scored all finger and wrist joints bilaterally on semi-quantitative 0-3 scales using three different FOI scoring methods. In the Berlin method, FOI enhancement was evaluated on three different images, defined as different phases based on the enhancement in the fingertips. A composite image (Prima Vista Mode, PVM) of the 240 first images was also assessed. The Copenhagen method assumed that inflamed tissues will demonstrate a more rapid FOI enhancement than the surrounding tissues, defining inflammation as sharply marginated enhancement over a joint area with clear delineation from surrounding tissues lasting ≥3 sec. The Stockholm method was evaluated in PVM format of 240 and 120 images in ‘temperature’ palette setting, with additional scrolling through the image sequence to detect ambiguous signals. To evaluate inter-reader reliability, we calculated the intraclass correlation coefficients (ICC) of the sum scores on patient level and weighted kappa values and prevalence and bias adjusted kappa values for ordinal scales (Pabak-OS) on joint level. Finally, we compared the averaged sum scores in the different joint groups in patients with erosive hand OA vs. RA using the Mann-Whitney test. Results The ICC of the sum scores was very good for the Stockholm method (0.83), and for Berlin PVM (0.93) and Phase 2 (0.83), while the Copenhagen method (0.65) and Berlin phase 3(0.73) showed good reliability. Berlin phase 1 showed fair reliability (0.30). On joint level we found moderate to good agreement with pabak-OS for all methods (table). Patients with erosive hand OA had significantly more enhancement in DIP joints across all methods, while PIP enhancement was more common in erosive hand OA for the Berlin PVM and Stockholm methods only. Enhancement in the 1st CMC was not detected in any of the methods, and no consistent differences were observed for the wrist (data not shown). Conclusion We found moderate to very good inter-reader reliability on patient level for all methods except for Berlin phase 1 and moderate to good agreement on joint level for all methods. FOI showed different enhancement patterns between erosive hand OA and RA, with more enhancement in the DIP joints in the OA patients across all methods, supporting its validity. Disclosure of Interests Øystein Maugesten: None declared, Sarah Ohrndorf: None declared, Daniel Glinatsi: None declared, Mads AmmitzbØll-Danielsen: None declared, Yogan Kisten: None declared, Mikkel Ǿstergaard Grant/research support from: Abbvie, Celgene, Centocor, Merck, Novartis, Consultant for: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, and UCB, Speakers bureau: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, and UCB, Lene Terslev Speakers bureau: Speakers fee from : Roche, Novartis, Pfizer, MSD, BMS, Celgene, Till Uhlig: None declared, Tore K. Kvien Grant/research support from: AbbVie, BMS, MSD, Pfizer, Roche and UCB., Consultant for: AbbVie, Biogen, BMS, Boehringer Ingelheim, Celgene, Celltrion, Eli Lilly, Hospira, Merck-Serono, MSD, Novartis, Oktal, Orion Pharma, Pfizer, Roche, Sandoz, Sanofi, Mylan and UCB, Speakers bureau: AbbVie, Biogen, BMS, Boehringer Ingelheim, Celgene, Celltrion, Eli Lilly, Hospira, Merck-Serono, MSD, Novartis, Oktal, Orion Pharma, Pfizer, Roche, Sandoz, Sanofi and UCB, Ida Kristin Haugen Grant/research support from: ADVANCE research grant from Pfizer, Consultant for: Advisory board AbbvieTable 1