Validation of the OMERACT Magnetic Resonance Imaging Joint Space Narrowing Score for the Wrist in a Multireader Longitudinal Trial.

Objective: To assess the intrareader and interreader agreement and sensitivity to change of the Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis Magnetic Resonance Imaging Joint Space Narrowing (RAMRIS-JSN) score in the rheumatoid arthritis (RA) wrist in a longitudinal multireader exercise.
Methods: Coronal T1-weighted MR image sets of 1 wrist from 20 patients with early RA were assessed twice for JSN at 17 sites at baseline and after 36 or 60 months by 4 readers blinded to patient data but not time order. The joints were scored 0-4 according to the OMERACT RAMRIS-JSN score. Intraclass correlation coefficients (ICC), smallest detectable change (SDC), percentage exact/close agreement (PEA/PCA), and standardized response mean (SRM) were calculated.
Results: Median baseline and change score was 10.3 and 1.9, respectively. Intrareader ICC for baseline and change scores was good (≥ 0.50) to very good (≥ 0.80) for all and 3 of 4 readers, respectively. Interreader ICC was very good for change (0.93), while poor for baseline score if all 4 readers were included (0.36), but very good if 1 reader was excluded (0.87). Intrareader and interreader SDC was low (2.34-3.18), except for the intrareader SDC for 1 reader (6.75). The mean PEA/PCA was high for baseline and change scores both within and between the readers (51.5-99.2), except for interreader baseline PEA (14.4). SRM was moderate for all readers (0.55-0.77).
Conclusion: The OMERACT RAMRIS-JSN score showed high overall intrareader and interreader reliability, and moderate sensitivity to change, supporting inclusion of the measure as part of the OMERACT RAMRIS system.