Fast joint design method for parallel excitation radiofrequency pulse and gradient waveforms considering off-resonance

Abstract

A fast parallel excitation pulse design algorithm to select and to order phase-encoding (PE) locations (also known as "spokes") of an Echo-Volumar excitation k-space trajectory considering B0 field inhomogeneity is presented. Recently, other groups have conducted research to choose optimal PE locations, but the potential benefit of considering B 0 field inhomogeneity during PE location selection or their ordering has not been fully investigated. This article introduces a novel fast greedy algorithm to determine PE locations and their order that takes into account the off-resonance effects. Computer simulations of the proposed algorithm for B 1 field inhomogeneity correction demonstrate that it not only improves excitation accuracy but also provides an effective ordering of the PE locations. © 2012 Wiley Periodicals, Inc.