Projective imaging of pulsatile flow with magnetic resonance.

Noninvasive angiography with magnetic resonance is demonstrated. Signal arising in all structures except vessels that carry pulsatile flow is eliminated by means of velocity-dependent phase contrast, electrocardiographic gating, and image subtraction. Background structures become in effect transparent, enabling the three-dimensional vascular tree to be imaged by projection to a two-dimensional image plane. Image acquisition and processing are accomplished with entirely conventional two-dimensional Fourier transform magnetic resonance imaging techniques. When imaged at 0.6 tesla, vessels 1 to 2 millimeters in diameter are routinely detected in a 50-centimeter field of view with data acquisition times less than 15 minutes. Studies of normal and pathologic anatomy are illustrated in human subjects.