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Reduction of spectral ghost artifacts in high‐resolution echo‐planar spectroscopic imaging of water and fat resonances
Author(s) -
Du Weiliang,
Du Yiping P.,
Fan Xiaobing,
Zamora Marta A.,
Karczmar Gregory S.
Publication year - 2003
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10485
Subject(s) - resolution (logic) , spectral resolution , nuclear magnetic resonance , spectral line , imaging phantom , echo planar imaging , planar , physics , echo (communications protocol) , echo time , chemistry , optics , magnetic resonance imaging , computer science , artificial intelligence , medicine , computer network , computer graphics (images) , astronomy , radiology
Abstract Echo‐planar spectroscopic imaging (EPSI) can be used for fast spectroscopic imaging of water and fat resonances at high resolution to improve structural and functional imaging. Because of the use of oscillating gradients during the free induction decay (FID), spectra obtained with EPSI are often degraded by Nyquist ghost artifacts arising from the inconsistency between the odd and even echoes. The presence of the spectral ghost lines causes errors in the evaluation of the true spectral lines, and this degrades images derived from high‐resolution EPSI data. A technique is described for reducing the spectral ghost artifacts in EPSI of water and fat resonances, using echo shift and zero‐order phase corrections. These corrections are applied during the data postprocessing. This technique is demonstrated with EPSI data acquired from human brains and breasts at 1.5 Tesla and from a water phantom at 4.7 Tesla. Experimental results indicate that the present approach significantly reduces the intensities of spectral ghosts. This technique is most useful in conjunction with high‐resolution EPSI of water and fat resonances, but is less applicable to EPSI of metabolites due to the complexity of the spectra. Magn Reson Med 49:1113–1120, 2003. © 2003 Wiley‐Liss, Inc.