Real-time vs static scoring in musculoskeletal ultrasonography in patients with inflammatory hand osteoarthritis

Abstract

Objectives. Agreement between real-time and static ultrasonography has not been studied in musculoskeletal diseases. We studied this agreement in inflammatory hand OA. Methods. Ultrasonography was performed blinded to clinical information of 30 joints of 75 patients with hand OA, treated with prednisolone in a randomized placebo-controlled double-blind trial. Images were scored real-time at acquisition and stored images were scored static (paired in known chronological order) for inflammatory features and osteophytes (score 0–3). Agreement between methods was studied at joint level with quadratic weighted kappa. At patient level intra-class correlations (ICC) of sum scores and change in sum-scores (delta baseline—week 6) were calculated. Responsiveness of scoring methods was analysed with generalized estimating equations (GEE) with treatment as independent and ultrasonography findings as dependent variable. Results. Agreement at baseline was good to excellent at joint level (kappa 0.72–0.88) and moderate to excellent at patient level (ICC 0.58–0.91). Agreement for change in sum scores was poor to fair for synovial thickening and effusion (ICC 0.18 and 0.34, respectively), while excellent for Doppler signal (ICC 0.80). Real-time ultrasonography discriminated between prednisolone and placebo with a mean between-group difference of synovial thickening of 2.5 (95% CI: 4.7, 0.3). Static ultrasonography did not show a decrease in synovial thickening. Conclusion. While cross-sectional agreement between real-time and static ultrasonography is good, static ultrasonography measurement of synovial thickening did not show responsiveness to prednisone therapy while real-time ultrasonography did. Therefore, when ultrasonography is used in clinical trials, real-time dynamic scoring should remain the standard for now.