One of the biggest challenges in caring for patients with Rheumatoid Arthritis (RA) and Juvenile Rheumatoid Arthritis (JRA) is quantifying the degree of disease activity in any given joint. We have built a prototype device using well-established sensors to rapidly quantify surface swelling and heat in arthritic joints. The goal of our studies is to test the hypothesis that this Imager can improve the clinical assessment of arthritis.