Objectives: To describe a novel scoring system for the assessment of tenosynovitis by magnetic resonance imaging in rheumatoid arthritis (RA) patients, and assess its intra- and inter-reader reliability in a multi-reader, longitudinal setting.
Methods: Flexor and extensor tenosynovitis were evaluated at the level of the wrist in 10 different anatomical areas, graded semi-quantitatively from grade 0 to 3 (total score 0-30), based on the the maximum width of post-contrast enhancement within each anatomical area on axial T1-weighted MR-images. Ten sets of baseline and 1-year follow-up MR images of the wrists of RA patients with early and established disease were scored independently by 4 readers twice on 2 consecutive days. Intra- and inter-reader agreements were evaluated.
Results: The intrareader intraclass correlation coefficients (ICCs) were high for status scores (median ICCs 0.84-0.88) and slightly lower for change score (0.74). The smallest detectable difference (SDD) in % of the maximum score was 11.2-11.5% for status scores and 13.3% for change scores. Inter-reader single-measure ICCs were acceptable for both status scores (median 0.73- 0.74) and change scores (0.67), while average-measures ICCs were very high for both status and change score (all >0.94). The median scoring time per patient (baseline and follow-up images) was 7 (range 3-10) minutes.
Conclusions: The introduced tenosynovitis scoring system demonstrates a high degree of multi-reader reliability, is feasible, and may be used as an adjuvant to the existing OMERACT RAMRIS score, allowing improved quantification of inflammatory soft-tissue changes in RA patients.
- magnetic resonance imaging
- rheumatoid arthritis