The clinical utility of musculoskeletal ultrasound for disease activity evaluation and therapeutic response prediction in rheumatoid arthritis patients: A narrative review

Rheumatoid arthritis (RA) is characterized by persistent synovitis and joint/bone destruction. There is an unmet need to predict the therapeutic response to disease-modifying anti-rheumatic drugs (DMARDs) and achieve a treat-to-target goal. Musculoskeletal ultrasound (MSUS) is widely used to identify structural change and assess therapeutic response in RA. This review aims to summarize the available evidence regarding the clinical application of MSUS in evaluating disease activity and predicting therapeutic responses to DMARDs. We searched the MEDLINE database using the PubMed interface and reviewed English-language literature from 2000 to 2022. This review focuses on the updated role of MSUS in assessing disease activity and predicting therapeutic responses to DMARDs in RA patients. MSUS is now widely applied to identify articular structural change and assess the disease activity of RA. Combined use of gray scale and power Doppler MSUS is also superior to clinical assessment and laboratory examination in evaluating disease activity of RA. With portable use, good viability, and high sensitivity to articular inflammation, MSUS would be useful in assessing therapeutic response to biologic/targeted synthetic DMARDs (b/tsDMARDs) in RA patients. Given MSUS could also detect subclinical inflammation in a substantial proportion of RA patients with clinical remission, it is recommended to assess b/tsDMARDs-treated RA patients who have achieved low disease activity or remission. Although substantial literature data have revealed clinical utility of MSUS for monitoring disease activity and evaluating therapeutic response in RA patients, the evidence regarding its predictive value for the effectiveness of b/tsDMARDs is limited.