As an ultrasound technique, color Doppler is used to evaluate blood flow through vessels. It does this by measuring the change in frequency of the ultrasound waves as they bounce off moving objects. This information is then used to create a color-coded map of the blood flow.

Color Doppler can be used to assess many different medical conditions, including cardiovascular disease, peripheral vascular disease, and renal artery stenosis. In addition, it can be used to evaluate blood flow in fetal vessels and in the placenta. Color Doppler is a noninvasive and safe procedure that has no known risks or side effects.