Imaging-detected tenosynovitis in rheumatoid arthritis: from early diagnosis to disease monitoring

Abstract This narrative review provides an updated overview of the pivotal role of imaging-detected tenosynovitis in the diagnosis and management of rheumatoid arthritis (RA). Tenosynovitis emerges as one of the earliest pathological events in inflammatory arthritis, and its histopathological features are indistinguishable from those of joint synovitis. Both musculoskeletal ultrasound (MSUS) and magnetic resonance imaging (MRI) are the principal imaging modalities for its detection; MSUS demonstrates high specificity—particularly when compared with healthy controls or individuals who do not progress to RA—whereas MRI generally offers superior sensitivity for identifying early inflammatory changes. Importantly, tenosynovitis is a strong predictor of RA development, with studies highlighting its independent association with progression to RA and its ability to enhance the diagnostic performance of established classification criteria. It is correlated with the clinical and laboratory parameters of disease activity. Additionally, imaging-detected tenosynovitis is highly responsive following disease-modifying antirheumatic drug (DMARD) therapy. This makes it valuable for monitoring disease activity and has led to its incorporation into various ultrasound scoring systems. Its prognostic value is evident in predicting disease flares and radiographic progression in RA patients. While limited, emerging evidence also points to its potential in predicting treatment response.