Optimization and validation of methods for mapping of the radiofrequency transmit field at 3T.

Détails

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Etat: Public
Version: de l'auteur⸱e
ID Serval
serval:BIB_93C85C29EB9F
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Optimization and validation of methods for mapping of the radiofrequency transmit field at 3T.
Périodique
Magnetic Resonance in Medicine
Auteur⸱e⸱s
Lutti A., Hutton C., Finsterbusch J., Helms G., Weiskopf N.
ISSN
1522-2594 (Electronic)
ISSN-L
0740-3194
Statut éditorial
Publié
Date de publication
2010
Volume
64
Numéro
1
Pages
229-238
Langue
anglais
Notes
Publication types: Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't ; Validation StudiesPublication Status: ppublish
Résumé
MRI techniques such as quantitative imaging and parallel transmit require precise knowledge of the radio-frequency transmit field (B(1) (+)). Three published methods were optimized for robust B(1) (+) mapping at 3T in the human brain: three-dimensional (3D) actual flip angle imaging (AFI), 3D echo-planar imaging (EPI), and two-dimensional (2D) stimulated echo acquisition mode (STEAM). We performed a comprehensive comparison of the methods, focusing on artifacts, reproducibility, and accuracy compared to a reference 2D double angle method. For the 3D AFI method, the addition of flow-compensated gradients for diffusion damping reduced the level of physiological artifacts and improved spoiling of transverse coherences. Correction of susceptibility-induced artifacts alleviated image distortions and improved the accuracy of the 3D EPI imaging method. For the 2D STEAM method, averaging over multiple acquisitions reduced the impact of physiological noise and a new calibration method enhanced the accuracy of the B(1) (+) maps. After optimization, all methods yielded low noise B(1) (+) maps (below 2 percentage units), of the nominal flip angle value (p.u.) with a systematic bias less than 5 p.u. units. Full brain coverage was obtained in less than 5 min. The 3D AFI method required minimal postprocessing and showed little sensitivity to off-resonance and physiological effects. The 3D EPI method showed the highest level of reproducibility. The 2D STEAM method was the most time-efficient technique.
Mots-clé
Adult, Artifacts, Brain Mapping, Female, Head/radiography, Humans, Magnetic Resonance Imaging/methods, Male
Pubmed
Web of science
Open Access
Oui
Création de la notice
08/07/2013 9:22
Dernière modification de la notice
20/08/2019 14:56
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