Reliability and Availability of the 2017 EULAR-OMERACT Scoring System for Ultrasound Synovitis Assessment: Results From a Training and Reading Exercise.

OBJECTIVE

To evaluate the availability and reliability of the European League Against Rheumatisms Outcome Measures in Rheumatology Synovitis (EULAR-OMERACT) scoring system among radiologists with different levels of musculoskeletal ultrasound (US) experience in assessing synovitis in patients with rheumatoid arthritis (RA).

METHOD

The patients with RA were retrospectively recruited from January 2020 to March 2022. Five radiologists with different levels of US experience were recruited for the reader study (R1-5), which included two parts. The participating radiologists first read 120 gray-scale (GS) and 120 Doppler US images twice, before and after a standard training program. In the first part, they semi-quantitatively scored the images from 0 to 3 based on the EULAR-OMERACT scoring system. In the second part, they read and scored 165 paired GS and Doppler images two times in 1 month using the EULAR-OMERACT scoring system. The correlation between the sum of the GSUS and power Doppler US (PDUS) image scores and the clinical scores was assessed.

RESULT

The intra-rater agreement of the five radiologists was good for the EULAR-OMERACT scoring system, with κ ranging from 0.72 to 0.94 for GSUS and from 0.81 to 0.97 for PDUS. The inter-rater agreement among the experts was good to very good in the EULAR-OMERACT scoring system (κ: 0.76-0.94 for GSUS and 0.80-0.96 for PDUS). The sum of the GSUS and PDUS scores in the EULAR-OMERACT scoring system was moderate to highly positively correlated with the clinical scores (ρ of GSUS: 0.58-0.79, ρ of PDUS: 0.57-0.70 for disease activity score in 28 joints C-reactive protein) after training.

CONCLUSION

The EULAR-OMERACT scoring system is a reliable method for evaluating synovitis in RA and shows potential for disease assessment and follow-up in patients with RA.