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Reproducibility measurement of glutathione, GABA, and glutamate: Towards in vivo neurochemical profiling of multiple sclerosis with MR spectroscopy at 7T
Author(s) -
Prinsen Hetty,
de Graaf Robin A.,
Mason Graeme F.,
Pelletier Daniel,
Juchem Christoph
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25356
Subject(s) - reproducibility , glutamate receptor , glutathione , metabolite , chemistry , neurochemical , multiple sclerosis , medicine , biochemistry , chromatography , immunology , receptor , enzyme
Purpose To determine the reproducibility of a comprehensive single‐session measurement of glutathione (GSH), γ‐aminobutyric acid (GABA), glutamate, and other biochemicals implicated in the pathophysiology of multiple sclerosis (MS) in the human brain with 1 H magnetic resonance spectroscopy (MRS). Materials and Methods Five healthy subjects were studied twice in separate 1‐hour sessions at 7T. One MS patient was also scanned once. GSH and GABA were measured with J‐difference editing using a semilocalized by adiabatic selective refocusing sequence (semi‐LASER, TE = 72 msec). A stimulated echo acquisition mode sequence (STEAM, TE = 10 msec) was used to detect glutamate along with the overall biochemical profile. Spectra were quantified with LCModel. Quantification accuracy was assessed through Cramer‐Rao lower bounds (CRLB). Reproducibility of the metabolite quantification was tested using coefficients of variation (CoV). Results CRLB were ≤7% for GSH, GABA, and glutamate and average CoV of 7.8 ± 3.2%, 9.5 ± 7.0%, and 3.2 ± 1.7% were achieved, respectively. The average test/retest concentration differences at this measurement reproducibility and quantification accuracy were smaller for GABA and glutamate than intersubject variations in metabolite content with CoV ratios of 0.6 and 0.8, respectively. As proof of principle, GSH, GABA, and glutamate were also detected in an MS patient. Conclusion GSH, GABA, glutamate, and other metabolites relevant in MS can be quantified at 7T with high accuracy and reproducibility in a single 1‐hour session. This methodology might serve as a clinical research tool to investigate biochemical markers associated with MS. Level of Evidence: 2 J. Magn. Reson. Imaging 2017;45:187–198.