Normal coronary physiology assessed by intracoronary Doppler ultrasound.

There is a natural need to measure flow in normal as well as diseased coronary arteries since the reestablishment of normal flow is the aim of most coronary interventions. Miniaturization has enabled positioning both proximal and distal within the coronary anatomy and improved accuracy of Doppler velocity measurements. Measurement of coronary flow reserve adds functional data to coronary angiographic anatomic description, and quantitation of flow, achieved by combining Doppler velocity. Although new techniques involving transthoracic Doppler and magnetic resonance imaging are currently being developed and refined to measure coronary flow velocity and volume flow noninvasively, the role of intracoronary Doppler remains secure particularly for the coronary interventional physician.