Single-shot, variable flip-angle slice-selective excitation with four gradient-modulated adiabatic half-passage segments.
Adiabatic pulses, although useful in generating uniform spin nutation in the presence of inhomogeneous B1 fields, are limited for NMR imaging applications due to the lack of slice-selective excitation capability. Selective excitation techniques using gradient modulation have been introduced; however, present methods require either a minimum of two excitations or eight adiabatic segments. Here, a scheme is presented that allows single-shot, arbitrary flip-angle, and slice-selective excitation with only four adiabatic half-passage segments. The technique is demonstrated via computer simulation and experimental tests on a phantom. Furthermore, issues associated with the implementation of these gradient-modulated adiabatic pulses are discussed.
Hsu
E W
EW
Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710, USA. ehsu@orion.mc.duke.edu
Reeder
S B
SB
MacFall
J R
JR
D003198:Computer Simulation; D005583:Fourier Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity