Proliferative synovitis, an ultrasound pattern associated with ACPA-positive patients and erosive disease in rheumatoid arthritis.

Objectives: To analyse ultrasound (US) differences between rheumatoid arthritis (RA) patients according to autoantibody status and characterise the clinical and radiological features associated with the US pattern of seropositive patients.

Methods: We collected demographic and clinical data and bilateral hand US images of RA patients. We defined an extreme proliferative US pattern, encompassing synovial hypertrophy grade II-III with Power Doppler signal, which we called US proliferative synovitis (US PS).