Reliability of ultrasound grading traditional score and new global OMERACT-EULAR score system (GLOESS): results from an inter- and intra-reading exercise by rheumatologists

This study aims to test the reliability of ultrasound to graduate synovitis in static and video images, evaluating separately grayscale and power Doppler (PD), and combined. Thirteen trained rheumatologist ultrasonographers participated in two separate rounds reading 42 images, 15 static and 27 videos, of the 7-joint count [wrist, 2nd and 3rd metacarpophalangeal (MCP), 2nd and 3rd interphalangeal (IPP), 2nd and 5th metatarsophalangeal (MTP) joints]. The images were from six patients with rheumatoid arthritis, performed by one ultrasonographer. Synovitis definition was according to OMERACT. Scoring system in grayscale, PD separately, and combined (GLOESS-Global OMERACT-EULAR Score System) were reviewed before exercise. Reliability intra- and inter-reading was calculated with Cohen's kappa weighted, according to Landis and Koch. Kappa values for inter-reading were good to excellent. The minor kappa was for GLOESS in static images, and the highest was for the same scoring in videos (k 0.59 and 0.85, respectively). Excellent values were obtained for static PD in 5th MTP joint and for PD video in 2nd MTP joint. Results for GLOESS in general were good to moderate. Poor agreement was observed in 3rd MCP and 3rd IPP in all kinds of images. Intra-reading agreement were greater in grayscale and GLOESS in static images than in videos (k 0.86 vs. 0.77 and k 0.86 vs. 0.71, respectively), but PD was greater in videos than in static images (k 1.0 vs. 0.79). The reliability of the synovitis scoring through static images and videos is in general good to moderate when using grayscale and PD separately or combined.