A method for the contrast enhancement and reduction of artifacts in three-d
imensional (3D) magnetization-prepared (MP) magnetic resonance angiography
(MRA) sequences is presented. A common artifact in these sequences is a per
iodical signal loss inside the vessels at the slab-slab junctions due to pr
ogressive saturation of the blood spins. This effect may be overcome by num
erical optimization of the excitation pulses in dependence on sequence-rela
ted and physiological parameters. The feasibility of this method is shown i
n a phantom and an in vivo experiment by visualization of the carotid arter
ies and intracranial vessels. Furthermore, a method for contrast enhancemen
t in MRA by data postprocessing is proposed, based on appropriate filtering
of k-space data before Fourier transformation. This method is tested in tw
o in vivo experiments by visualization of the arteries in the head and leg
of healthy volunteers. (C) 1999 John Wiley & Sons, Inc.