Over the last decades, ultrasound (US) has undergone a dramatic evolution in the field of inflammatory joint diseases. Rheumatoid arthritis (RA) is probably the pathology that has most benefited from this development, both in terms of early diagnosis and monitoring of disease activity. The RA-induced morpho-structural changes can be effectively detected and measured by US, and US findings represent an additional advantage over clinical and laboratory evaluation, showing the face of the disease (i.e., proliferative synovitis) and revealing its aggressive behavior (i.e., presence of bone erosions not detectable by conventional radiography). The present review provides an overview of the main studies focusing on the value of US in the assessment of the patients with RA, and discussing the elementary lesions detectable by US (synovitis, bone erosion, cartilage damage, tenosynovitis and tendon damage), the scoring systems currently available and the scanning protocols in definite clinical settings (undifferentiated arthritis, early and long standing RA).
Keywords: Bone erosion; Rheumatoid arthritis; Scoring systems; Synovitis; Ultrasonography.