From a formal training program in musculoskeletal ultrasound (Msus) to a high reproducibility for msus ultrasound in rheumatoid arthritis

Objective: 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. Methods: 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. Interobserver reliability was assessed by unweight Light’s. Results: 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. Conclusion: 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.