BLOOD-FLOW MEASUREMENTS IN THE AORTA AND MAJOR ARTERIES WITH MR VELOCITY MAPPING

The purpose of this study was to measure antegrade and retrograde flow in the aorta and the major arterial pathways in the body noninvasivel y with cine magnetic resonance (MR) velocity mapping, to determine the hemodynamic significance of retrograde flow in arteries. Two hundred forty cine velocity maps for blood flow measurements were obtained at 29 sites in the aorta and the major arteries in 31 healthy human subje cts of varying age at rest. Synchronous or isolated antegrade and retr ograde flow was found in the entire aorta and in arteries supplying mu scles. No retrograde flow was found in arteries supplying internal org ans, such as the internal carotid or splanchnic arteries. The retrogra de flow in the aorta and the extremity arteries contributes substantia lly to supplying diastolic perfusion of internal organs such as the he art, brain, and kidneys. Antegrade flow tends to be helical in the tho racic aorta.