To assess the intra- and inter-observer reliability of Ultrasound (US) in scoring B-mode, Doppler synovitis and combined B-mode and Doppler synovitis scores in different peripheral joints of Rheumatoid Arthritis (RA) patients.
Four rheumatologists with a formal training in Musculoskeletal US (MSKUS) particularly focus on definitions and scoring synovitis on B-mode and Doppler mode participated in a patient- based reliability exercise on 16 active RA patients. The four rheumatologists independently and consecutively performed a B-mode and Power Doppler (PD) US assessment of 7 joints of each patient in two rounds in a blinded fashion. Each joint was semi quantitatively scored from 0 to 3 for B-mode Synovitis (BS), Doppler Synovitis (DS), and combined B-mode/Doppler synovitis (CS). Intraobserver reliability was assessed by Cohen's κ. Interobserver reliability was assessed by unweight Light's κ.
The mean prevalence of synovitis on B-mode was 83% of joints; scores ranging from grade 1 in 18% of joints, to grade 3 in 33%. In 55% of joints synovial PD signal was detected and the distribution of scores range from 14% of joints for grade 3, to 26% for grade 2. After a total of 448 joints scanned with 896 adquired images our intraobserver and interobserver reliability was good to excellent for most of the joints.
Formal, structured and continuous training in musculoskeletal ultrasound would bring a good to excellent reproducibility in rheumatological hands with a high reliability in real time acquisition BS, DS and CS modalities for scoring synovitis in patients with active rheumatoid arthritis.