Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI.

Détails

ID Serval
serval:BIB_39BF7C128948
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI.
Périodique
Journal of Magnetic Resonance
Auteur⸱e⸱s
Schmidt R., Mishkovsky M., Hyacinthe J.N., Kunz N., Gruetter R., Comment A., Frydman L.
ISSN
1096-0856 (Electronic)
ISSN-L
1090-7807
Statut éditorial
Publié
Date de publication
10/2015
Peer-reviewed
Oui
Volume
259
Pages
199-206
Langue
anglais
Notes
Publication types: Journal Article
Résumé
Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences - including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to compensate for the RF transmit inhomogeneities and thus improve sensitivity and image fidelity.
Mots-clé
Ultrafast MRI, Spatiotemporal encoding, B1 corrections, Swept pulses, Surface coil MRI
Pubmed
Web of science
Création de la notice
09/09/2015 16:30
Dernière modification de la notice
20/08/2019 13:29
Données d'usage