Journal Article Research Support, N.I.H., Extramural Ppublish 15 citations
PubMed: 33427349 DOI: 10.1002/mrm.28661
Optimization of adiabatic pulses for pulsed arterial spin labeling at 7 tesla: Comparison with pseudo-continuous arterial spin labeling.
Magn Reson Med 85(6):3227-3240
Authors: Kai Wang, Xingfeng Shao, Lirong Yan, Samantha J Ma, Jin Jin, Danny J J Wang
Affiliations
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA. Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
- Siemens Medical Solutions USA, Inc. Los Angeles, California, USA.
- Siemens Healthcare Pty Ltd, Brisbane, Australia.
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Abstract
PURPOSE
To optimize and evaluate adiabatic pulses for pulsed arterial spin labeling at ultrahigh field 7 tesla.
METHODS
Four common adiabatic inversion pulses, including hyperbolic secant, wideband uniform rate smooth truncation, frequency offset corrected inversion, and time-resampled frequency offset corrected inversion pulses, were optimized based on a custom-defined loss function that included labeling efficiency and inversion band uniformity. The optimized pulses were implemented in flow-sensitive alternating inversion recovery sequences and tested on phantom and 11 healthy volunteers with 2 constraints: 1) specific absorption rate normalized; and 2) equal peak RF amplitude, respectively. A pseudo-continuous arterial spin labeling sequence was implemented for comparison. Quantitative metrics such as perfusion and relative labeling efficiency versus residual tissue signal were calculated.
RESULTS
Among the 4 pulses, the wideband uniform rate smooth truncation pulse yielded the lowest loss in simulation and achieved a good balance between labeling efficiency and residual tissue signal from both phantom and in vivo experiments. Wideband uniform rate smooth truncation-pulsed arterial spin labeling showed significantly higher relative labeling efficiency compared to the other sequences (P < .01), whereas the perfusion signal was increased by 40% when the highest amplitude was used. The 4 pulsed arterial spin labeling sequences yielded comparable perfusion signals compared to pseudo-continuous arterial spin labeling but with less than half the specific absorption rate.
CONCLUSION
Optimized wideband uniform rate smooth truncation pulse with the highest amplitude allowed was recommended for 7 tesla pulsed arterial spin labeling.
MeSH
Tissues, Absorption, Pulse
Cited by
- Dynamic B field shimming for improving pseudo-continuous arterial spin labeling at 7 T. Magn Reson Med, 2025
- Whole-Cerebrum distortion-free three-dimensional pseudo-Continuous Arterial Spin Labeling at 7T. medRxiv, 2023
- Advanced design of MRI inversion pulses for inhomogeneous field conditions by optimal control. NMR Biomed, 2022
- Recent Technical Developments in ASL: A Review of the State of the Art. Magn Reson Med, 2022
- Optimization of pseudo-continuous arterial spin labeling at 7T with parallel transmission B1 shimming. Magn Reson Med, 2022
- High-Resolution Neurovascular Imaging at 7T: Arterial Spin Labeling Perfusion, 4-Dimensional MR Angiography, and Black Blood MR Imaging. Magn Reson Imaging Clin N Am, 2021