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Improved slice‐selective adiabatic excitation
Author(s) -
Balchandani Priti,
Glover Gary,
Pauly John,
Spielman Daniel
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24630
Subject(s) - excitation , pulse (music) , adiabatic process , pulse duration , resonance (particle physics) , materials science , wafer , nuclear magnetic resonance , chemistry , atomic physics , optics , physics , optoelectronics , detector , laser , quantum mechanics , thermodynamics
Purpose The purpose of this work is to design an improved Slice‐selective Tunable‐flip AdiaBatic Low peak‐power Excitation (STABLE) pulse with shorter duration and increased off‐resonance immunity to make it suitable for use in a greater range of applications and at higher field strengths. An additional aim is to design a variant of this pulse to achieve B 1 ‐insensitive, fat‐suppressed excitation. Methods The adiabatic SLR algorithm was used to generate a more uniform spectral pulse envelope for this improved radiofrequency pulse for adiabatic slice‐selective excitation, called STABLE‐2. Pulse parameters were adjusted to design a version of STABLE‐2 with a spectral null centered on lipids. Results In vivo images obtained of the human brain at 3 and 7 T demonstrate that STABLE‐2 provides robust, uniform, slice‐selective excitation over a range of B 1 values. Phantom and in vivo knee images obtained at 3 T demonstrate the effectiveness of STABLE‐2 for fat suppression. Conclusions STABLE‐2 achieves B 1 ‐insensitive slice‐selective excitation while providing greater off‐resonance immunity and a shorter pulse duration, when compared to the original STABLE pulse. In particular, the 9.8‐ms STABLE‐2 pulse provides slice selectivity over 120 Hz whereas the 21‐ms STABLE pulse is limited to 80 Hz off‐resonance. B 1 ‐Insensitive fat‐suppressed excitation may also be achieved by using a variant of this pulse. Magn Reson Med 71:75–82, 2014. © 2013 Wiley Periodicals, Inc.