Advances in the Application of Musculoskeletal Ultrasound in the Diagnosis of Rheumatoid Arthritis: A Review.

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that primarily targets the joints, causing persistent inflammation, progressive joint destruction, and functional disability. Early and accurate diagnosis is essential for initiating timely treatment and improving patient outcomes. Musculoskeletal ultrasound (MSUS), a non-invasive and real-time imaging technique, has attracted considerable interest for its high-resolution visualization and ability to assess joints dynamically. This narrative review synthesizes current literature on the role of MSUS in the diagnosis of RA, with particular emphasis on its unique value in the early detection of subclinical synovitis and in supporting the diagnosis of seronegative RA, where conventional serological markers are absent. MSUS enables sensitive detection of synovial hypertrophy, tenosynovitis, joint effusion, increased vascularity on power Doppler imaging, and early bone erosions, facilitating timely recognition of inflammatory activity and structural damage. Despite these advantages, limitations such as operator dependence and variability in standardization remain. Recent advances-including consensus-based EULAR-OMERACT definitions and scoring systems, standardised scanning protocols, and emerging artificial intelligence applications-have broadened the clinical value of MSUS, indicating promising opportunities for its incorporation into routine RA management. This article aims to synthesize existing evidence, address ongoing challenges, and explore future directions to further enhance the diagnostic and monitoring capabilities of MSUS in patients with RA.