1. A method of a) acquiring three-dimensional MR data from a patient's arteries and veins within a volume of interest (VOI) made up of voxels and b) displaying an image reconstructed from such three-dimensional MR data in such a manner as to visually distinguish the arteries from the veins, comprising: administering a bolus of an intravascular MR contrast agent to the patient's circulatory system in such a manner as to enhance the blood vessels; acquiring a plurality of three-dimensional dynamic MR datasets from the VOI, said dynamic dataset acquisition beginning after administration of the contrast medium and continuing for a sufficiently long time as to reflect contrast agent enhancement of all arterial and venous blood vessels within the VOI; acquiring a three-dimensional MR angiogram of the VOI after the contrast agent has reached equilibrium; computing, for each voxel within the VOI, enhancement of that voxel as a function of time post administration of the contrast agent; selecting parameters that distinguish enhancement of voxels relating to the patient's arteries from enhancement of voxels relating to the patient's veins; scaling intensity of each voxel in the MR angiogram in accordance with the selected parameters; and generating a maximum intensity projection reconstruction of the VOI from the MR angiogram in which voxel intensity has been scaled.