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Homonuclear J coupling effects in volume localized NMR spectroscopy: Pitfalls and solutions
Author(s) -
Yablonskiy Dmitriy A.,
Neil Jeffrey J.,
Raichle Marcus E.,
Ackerman Joseph J. H.
Publication year - 1998
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.1910390202
Subject(s) - homonuclear molecule , j coupling , nuclear magnetic resonance , amplitude , nuclear magnetic resonance spectroscopy , chemistry , signal (programming language) , voxel , pulse sequence , spectroscopy , artifact (error) , physics , optics , computer science , molecule , artificial intelligence , organic chemistry , quantum mechanics , programming language
It has been observed that the signal amplitude of multiplet resonances such as the 1H doublet resonance of lactate varies with pulse sequence timing when echo‐driven volume selective methods such as point resolved spectroscopy are used. Herein a standard vectorial description is presented for the mechanism of this artifact, which results from the chemical shift between homonuclear scalar‐coupled (i.e., J coupled) nuclei. The chemical shift causes the extent of a signal phase modulation to vary for different spatial regions of the excited voxel. This variation results in spatial interference effects that can lead to marked loss of signal intensity as well as corruption of the size and shape of the voxel from which signal is obtained. The phenomenon is substantial at an imaging field of 1.5 T and becomes especially pronounced at higher field strengths. Several strategies to avoid the artifact are provided.