Unpaired Adiabatic Refocusing Pulses for Volume Selection in Spectroscopic Imaging
de Graaf R, Rothman D, Sacolick L
Conventional volume selection by adiabatic pulses in spectroscopic imaging is done with pairs of identical pulses. This refocuses the non-linear phase shift introduced by AFP pulses which would otherwise cause intravoxel signal loss. Here we show that sequentially applying single AFP pulses at 45 angles will give good phase refocusing with little signal loss for spectroscopic imaging. Conventional AFP pulses were replaced by FOCI pulses to decrease chemical shift displacement without increasing peak RF power. This new sequence provides good volume selection with half the power and echo time as for a paired AFP sequence.