Power Doppler and spectral Doppler measurements of knee-joint synovitis in rheumatoid arthritis patients with superficial pattern signals and in those with deep pattern signals

Color fraction as a useful method of imaging synovium vascularization in patients with high activity of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease with joint inflammation and destruction as the main features that appears with prevalence of 1 to 2% of the general population. Women are three times more likely to suffer from RA than men. Rheumatoid arthritis occurs at any age but commonly over 40-50 years old. In the course of RA each joint may be involved but most frequently the proximal interphalangeal and metacarpophalangeal joints of the hands, wrists, and also small joints of the feet are affected. Symmetrical joint swelling with overgrowth of synovium and hypervascularization confirmed in power Doppler ultrasound imaging are very characteristic for RA. Quantification of vascularization with the color fraction index may be a useful tool to monitor disease activity and in evaluation of inflammation in scientific research. This article aims to present this imaging diagnostic method based on the literature.