Contrast enhancement and artifact reduction in magnetization-prepared MR angiography

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.