Assessing rheumatoid arthritis disease activity with ultrasound

In practice, composite indices are used for rheumatoid arthritis (RA) disease activity evaluation. Despite valid and widely used, not rarely composite indices miss accuracy. Ultrasound (US) is more precise than clinical examination in synovitis appraisal. US-based disease activity estimation depends on the detection of synovitis. The most common synovitis abnormalities are proliferation, effusion, and neoangiogenesis. Gray scale ultrasound identifies synovial hypertrophy and effusion with its good soft tissue contrast. Additionally, power Doppler ultrasound depicts neoangiogenesis within synovia, remarking local inflammation. Several studies have combined local US findings to develop a patient level disease activity index. Most of them summed selected joint scores in an overall score of disease activity and evaluated its correlation with clinical composite indexes. To be incorporated into clinical practice, an overall US score must have some fundamental characteristics such as reproducibility, viability, and sensitivity to change over time. In global US score development, finding the joints that truly estimate individual disease activity is highly challenging. This article presents an up-to-date literature review on assessing RA disease activity with US and depicts the challenges in finding the perfect global US score.