In the Doppler tests, we can estimate the velocity of blood flowing in an artery. This is useful in assessing the amount of occlusion present. Just like white water in a river, the narrower the river, the faster it flows to get the same amount of water from point A to point B. The arteries are no different. The adjacent picture is a patient getting a Doppler of the carotid arteries in the neck. We have used before and after Doppler studies to show the efficacy of chelation in blocked neck(carotid) (papers 5,Â 23, 27) and kidney (renal) arteries (Paper # 32).