What are image findings in RA?

X ray (gold std for diagnosing damage in RA, 1st sign is soft tissue swelling, perarticular osteopenia, erosions joint space narrowing (which is diagnostic even if negative labs). Erosions occur rapidly 50% first year and 70% 5 years, important to know that first erosion is at MTP5, MTP before MCP. But X ray is limited since it needs 2 years to be visible) US (of hands and feet, earlier detection of erosion, shows joint, inflammation, tendon, angiogenesis, synovium, early detection subclinical synovitis, important to know common presentation is extensor carpi ulnaris tenosynovitis which is pathogneumonic) Others (MRI for early dx and staging not routinely used)