4868501 Method and means for magnetic resonance spin-echo imaging using an adiabatic three pi pulse sequence

Abstract

An adiabatic pulse suitable for generating selective spin echoes for both MR imaging and spectroscopy is described. The pulse requires no gradient reversal to achieve phase compensation. Like adiabatic inversion pulses the new pulse performs a π rotation for any amplitude exceeding a threshold. Unlike inversion pulses, this pulse leaves no phase variation across the slice. The pulse is actually a composite consisting of a 2π and a π pulse. The 2π pulse merely compensates for the phase of the π phase; it performs no net rotation. This compensation is immune to RF inhomogeneity and nonlinearity.