View in EDS

Calibration‐Free GRAPE pTx Pulses for Homogeneous Spatial‐Selective Excitation at 7T.

Saved in:
Bibliographic Details
Title: Calibration‐Free GRAPE pTx Pulses for Homogeneous Spatial‐Selective Excitation at 7T.
Authors: Löwen, Daniel1 (AUTHOR), Pracht, Eberhard D.1 (AUTHOR), Veldmann, Marten1 (AUTHOR), Gras, Vincent2 (AUTHOR), Mauconduit, Franck2 (AUTHOR), Boulant, Nicolas2 (AUTHOR), Stöcker, Tony1,3 (AUTHOR) tony.stoecker@dzne.de
Source: Magnetic Resonance in Medicine. Jun2026, Vol. 95 Issue 6, p3104-3115. 12p.
Subjects: Homogeneity, Magnetic resonance imaging, Bloch equations, Signal-to-noise ratio
Abstract: Purpose: Extend the universal pulse GRAPE formalism to pulses with a defined spectral response, and apply the concept to spatial selection. Methods: We added Bloch simulations at several frequencies for each voxel to the pulse calculation to create universal spectrally‐selective GRAPE pulses. With a superimposed constant gradient field spatial selection was achieved. The method was tested in slice‐ and slab‐selective imaging experiments. Results: Universal spatially‐selective GRAPE pulses increased FA homogeneity and SNR. In 2D gradient echoes, the SNR could be increased by approximately 6% compared to CP pulses, and in a slab‐selective TSE sequence, the SNR increased by 29% against kT‐spokes pulses. Additionally, the slab‐selective GRAPE pulse proved to be more robust against B0 deviations and is significantly shorter in comparison to kT‐spokes pulses while maintaining a similar FA homogeneity. Conclusion: Spatially‐selective universal GRAPE pulses exhibit superior performance compared to kT‐spokes pulses. These short and robust pTx pulses hold potential for enhancing a wide range of imaging applications, thereby advancing 7T MRI technology closer to clinical use. [ABSTRACT FROM AUTHOR]
Copyright of Magnetic Resonance in Medicine is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:Purpose: Extend the universal pulse GRAPE formalism to pulses with a defined spectral response, and apply the concept to spatial selection. Methods: We added Bloch simulations at several frequencies for each voxel to the pulse calculation to create universal spectrally‐selective GRAPE pulses. With a superimposed constant gradient field spatial selection was achieved. The method was tested in slice‐ and slab‐selective imaging experiments. Results: Universal spatially‐selective GRAPE pulses increased FA homogeneity and SNR. In 2D gradient echoes, the SNR could be increased by approximately 6% compared to CP pulses, and in a slab‐selective TSE sequence, the SNR increased by 29% against kT‐spokes pulses. Additionally, the slab‐selective GRAPE pulse proved to be more robust against B0 deviations and is significantly shorter in comparison to kT‐spokes pulses while maintaining a similar FA homogeneity. Conclusion: Spatially‐selective universal GRAPE pulses exhibit superior performance compared to kT‐spokes pulses. These short and robust pTx pulses hold potential for enhancing a wide range of imaging applications, thereby advancing 7T MRI technology closer to clinical use. [ABSTRACT FROM AUTHOR]
ISSN:07403194
DOI:10.1002/mrm.70266