Fast‐kz three‐dimensional tailored radiofrequency pulse for reduced B1 inhomogeneity

Abstract

This article presents a small‐flip‐angle, three‐dimensional tailored RF pulse that excites thin slices with an adjustable quadratic in‐plane spatial variation. The quadratic spatial variation helps to compensate for the loss in image uniformity using a volume coil at 3 T due to the wavelike properties of the RF field. The pulse is based on a novel “fast‐k_z” design that uses a series of slice‐select subpulses along k_z and phase encoding “blips” along k_x–k_y. The method is demonstrated by acquiring a series of 5‐mm‐thick T₂‐weighted images of the human brain at 3 T using pulses 4.8 ms in length with a 45 ° flip angle. Magn Reson Med, 2006.