Gilles A, Nagel AM, Madelin G. Multipulse sodium magnetic resonance imaging for multicompartment quantification: Proof-of-concept.
Sci Rep 2017;
7:17435. [PMID:
29234043 PMCID:
PMC5727256 DOI:
10.1038/s41598-017-17582-w]
[Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/27/2017] [Indexed: 12/18/2022] Open
Abstract
We present a feasibility study of sodium quantification in a multicompartment model of the brain using sodium (23Na) magnetic resonance imaging. The proposed method is based on a multipulse sequence acquisition and simulation at 7 T, which allows to differentiate the 23Na signals emanating from three compartments in human brain in vivo: intracellular (compartment 1), extracellular (compartment 2), and cerebrospinal fluid (compartment 3). The intracellular sodium concentration C1 and the volume fractions α1, α2, and α3 of all respective three brain compartments can be estimated. Simulations of the sodium spin 3/2 dynamics during a 15-pulse sequence were used to optimize the acquisition sequence by minimizing the correlation between the signal evolutions from the three compartments. The method was first tested on a three-compartment phantom as proof-of-concept. Average values of the 23Na quantifications in four healthy volunteer brains were α1 = 0.54 ± 0.01, α2 = 0.23 ± 0.01, α3 = 1.03 ± 0.01, and C1 = 23 ± 3 mM, which are comparable to the expected physiological values \documentclass[12pt]{minimal}
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\begin{document}$${{\boldsymbol{\alpha }}}_{{\bf{1}}}^{{\boldsymbol{theory}}}$$\end{document}α1theory ∼ 0.6, \documentclass[12pt]{minimal}
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\begin{document}$${{\boldsymbol{\alpha }}}_{{\bf{2}}}^{{\boldsymbol{theory}}}$$\end{document}α2theory ∼ 0.2, \documentclass[12pt]{minimal}
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\begin{document}$${{\boldsymbol{\alpha }}}_{{\bf{3}}}^{{\boldsymbol{theory}}}$$\end{document}α3theory ∼ 1, and \documentclass[12pt]{minimal}
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\begin{document}$${{\boldsymbol{C}}}_{{\bf{1}}}^{{\boldsymbol{theory}}}$$\end{document}C1theory ∼ 10–30 mM. The proposed method may allow a quantitative assessment of the metabolic role of sodium ions in cellular processes and their malfunctions in brain in vivo.
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