4D magnetic resonance velocity mapping of blood flow patterns in the aortain young vs. elderly normal subjects

Four-dimensional magnetic resonance MR velocity mapping was developed to st udy normal now patterns in the thoracic aorta using time-resolved cardiac g ated three-directional velocity data. Sixteen normal subjects were studied, one young group (average age 31 years) and one group with elderly people ( average age 72 years). Blood flowed in a right-handed helix from the ascend ing aorta to the aortic arch, A straight flow pattern or a left-handed heli x was seen in the descending aorta. Blood now was never parabolic. Blood fl owed forward in early systole, retrograde in mid-to-end systole, and forwar d again in diastole in all subjects as a basic pattern. Continuous retrogra de now over a long distance was not seen, but blood entered a retrograde no w column at various levels, In young people blood passed from the aortic va lve to the mid-descending aorta in less than one heartbeat, In people in th eir sixties It took two heartbeats and in people older than 78 years, it to ok three heartbeats. The maximum systolic forward velocities were higher in young subjects than in elderly while the retrograde velocities were lower. (C) 1999 Wiley-Liss, Inc.