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Gradient and stimulated echo (GRASTE) imaging
Author(s) -
Finsterbusch Jürgen,
Frahm Jens,
Koch Martin A.
Publication year - 2006
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.20754
Subject(s) - physics , nuclear magnetic resonance , echo (communications protocol) , gradient echo , robustness (evolution) , sensitivity (control systems) , phase (matter) , spin echo , acoustics , computer science , optics , magnetic resonance imaging , chemistry , electronic engineering , medicine , computer network , biochemistry , quantum mechanics , gene , engineering , radiology
As a modification of single‐shot stimulated echo acquisition mode (STEAM) MRI, a gradient and stimulated echo (GRASTE) sequence is presented that acquires multiple gradient echoes in addition to each stimulated echo. While “contiguous” GRASTE exploits all stimulated echoes for the central part of k ‐space and the gradient echoes for outer lines, “interleaved” GRASTE assigns all echoes of a particular readout interval to directly neighboring lines. Phase distortions may be corrected by the reference signals of a single readout interval without phase encoding. Experimental results obtained for the human brain demonstrate that contiguous GRASTE yields up to 30% better SNR per acquisition time than conventional single‐shot STEAM due to a better efficiency and maintains most of its robustness. Interleaved GRASTE can improve the SNR by a factor of 2 because of the possibility of using larger flip angles in the readout interval. However, its more pronounced sensitivity to off‐resonance effects requires short echo trains. Magn Reson Med, 2006. © 2005 Wiley‐Liss, Inc.