Variable-density spiral 3D tailored RF pulses

A variable-density spiral method is presented for reducing three-dimensional tailored radiofrequency pulse duration. Pulse length reductions of 21-32% are possible, with only a small error in the desired excitation profile. The method is demonstrated using simulations, phantom experiments, and T-2(*)-weighted images of brain regions with susceptibility-induced intravoxel dephasing. Four 19.7-ms shots were needed to excite a 5-mm-thick slice with reduced susceptibility artifacts in the sinus region at 3T. Magn Reson Med 50: 1100-1106, 2003. (C) 2003 Wiley-Liss, Inc.