Is ultrasound a validated imaging tool for the diagnosis and management of synovitis in juvenile idiopathic arthritis? A systematic literature review

Objective Ultrasound (US) has been shown to be a sensitive tool for evaluating synovitis in rheumatoid arthritis. However, the validity of US has not yet been established in juvenile idiopathic arthritis (JIA). The purpose of this study was to assess the validity of US for detecting synovitis for both diagnosis and followup in JIA. Methods A systematic literature search in Embase and PubMed was performed before February 25, 2011. Selection criteria included original articles on children, JIA, US, Doppler, synovitis, and management published in the English language. Data were extracted from the articles meeting the inclusion criteria, particularly those focused on the US definition of synovitis, scoring systems used, and metric properties studied. The type and number of joints tested, study design, and quality of the studies were assessed. Results Twenty studies were identified using US to assess synovitis in JIA. The knee was the joint most commonly studied in these articles. There was heterogeneity regarding the US definition and quantification of synovitis. Synovitis was commonly assessed by using gray scale and only a few studies included the Doppler technique. Construct validity was reported in 80% of articles, including the clinical examination as the main comparator. US demonstrated higher sensitivity in detecting synovitis as compared to clinical examination. Few studies reported US reliability and responsiveness in JIA. Conclusion US is a valuable tool for detecting synovitis in JIA, and demonstrated higher sensitivity in assessing synovitis as compared to clinical examination. However, further studies are needed for evaluating the reliability and responsiveness to assess synovitis changes over time.