Minimization of Nyquist ghosting for echo-planar imaging at ultra-high fields based on a "negative readout gradient" strategy.

Détails

ID Serval
serval:BIB_EC8D61037BB7
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Minimization of Nyquist ghosting for echo-planar imaging at ultra-high fields based on a "negative readout gradient" strategy.
Périodique
Journal of Magnetic Resonance Imaging
Auteur(s)
van der Zwaag W., Marques J.P., Lei H., Just N., Kober T., Gruetter R.
ISSN
1522-2586[electronic]
Statut éditorial
Publié
Date de publication
2009
Volume
30
Numéro
5
Pages
1171-1178
Langue
anglais
Résumé
PURPOSE:
To improve the traditional Nyquist ghost correction approach in echo planar imaging (EPI) at high fields, via schemes based on the reversal of the EPI readout gradient polarity for every other volume throughout a functional magnetic resonance imaging (fMRI) acquisition train.
MATERIALS AND METHODS:
An EPI sequence in which the readout gradient was inverted every other volume was implemented on two ultrahigh-field systems. Phantom images and fMRI data were acquired to evaluate ghost intensities and the presence of false-positive blood oxygenation level-dependent (BOLD) signal with and without ghost correction. Three different algorithms for ghost correction of alternating readout EPI were compared.
RESULTS:
Irrespective of the chosen processing approach, ghosting was significantly reduced (up to 70% lower intensity) in both rat brain images acquired on a 9.4T animal scanner and human brain images acquired at 7T, resulting in a reduction of sources of false-positive activation in fMRI data. CONCLUSION: It is concluded that at high B(0) fields, substantial gains in Nyquist ghost correction of echo planar time series are possible by alternating the readout gradient every other volume.
Mots-clé
Nyquist ghost, Ghost correction, EPI, FMRI, Nyquist ghost, ghost correction, EPI, FMRI
Pubmed
Web of science
Création de la notice
20/11/2009 10:25
Dernière modification de la notice
03/03/2018 22:29
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