@article {Poulsenjrheum.200084, author = {Anna EF Poulsen and Mette B Axelsen and Ren{\'e} P Poggenborg and Iris Eshed and Simon Krabbe and Daniel Glinatsi and Jakob M M{\o}ller and Mikkel {\O}stergaard}, title = {Whole-Body MRI in Psoriatic Arthritis, Rheumatoid Arthritis And Healthy Controls {\textendash} Interscan, Intrareader and Interreader Agreement and Distribution of Lesions}, elocation-id = {jrheum.200084}, year = {2020}, doi = {10.3899/jrheum.200084}, publisher = {The Journal of Rheumatology}, abstract = {Objective Whole-body MRI (WBMRI) is promising for monitoring patients{\textquoteright} global disease activity in inflammatory joint diseases. The validation of WBMRI is limited; no studies have evaluated the test-retest agreement (interscan agreement) and only few have assessed the intra- and interreader agreement. Therefore we examined the interscan agreement of WBMRI in patients with psoriatic arthritis (PsA), rheumatoid arthritis (RA) and healthy controls (HC); and secondly evaluated the intraand interreader agreement and agreement with conventional hand MRI and determined the distribution of lesions. Methods WBMRI was performed twice with a one-week interval in 14 patients with PsA, 10 with RA and 16 HC. Images were anonymized and read in pairs with unknown chronological order by experienced readers according to the OMERACT WBMRI, the Canada-Denmark MRI and the RAMRIS/PsAMRIS scoring systems. Ten image sets were re-anonymized for assessment of intraand interreader agreement. Agreement was calculated on lesion level by percentage exact agreement (PEA) and Cohen{\textquoteright}s kappa, and for sum scores by absolute agreement single-measure intraclass correlation coefficient (ICC). Results WBMRI of the spine and peripheral joints and entheses generally showed moderate to almost perfect interscan agreement with PEA ranging from 95-100\%, kappa 0.71-1.00 and ICC 0.95-1.00. Intra- and interreader data generally showed moderate to almost perfect agreement. Agreement with conventional MRI varied. More lesions were found in patients than HC. Conclusion WBMRI showed good interscan agreement, implying that repositioning of the patient between examinations does not markedly affect scoring of lesions. Intra- and interreader agreement was moderate to almost perfect.}, issn = {0315-162X}, URL = {https://www.jrheum.org/content/early/2020/06/09/jrheum.200084}, eprint = {https://www.jrheum.org/content/early/2020/06/09/jrheum.200084.full.pdf}, journal = {The Journal of Rheumatology} }