Which prior knowledge? Quantification of in vivo brain 13C MR spectra following 13C glucose infusion using AMARES

Authors

  • Bernard Lanz,

    1. Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
    2. Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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  • João M. N. Duarte,

    1. Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
    2. Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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  • Nicolas Kunz,

    1. Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
    2. Department of Pediatrics, University of Geneva, Geneva, Switzerland
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  • Vladimir Mlynárik,

    1. Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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  • Rolf Gruetter,

    1. Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
    2. Department of Radiology, University of Geneva, Geneva, Switzerland
    3. Department of Radiology, University of Lausanne, Lausanne, Switzerland
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  • Cristina Cudalbu

    Corresponding author
    1. Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
    • Laboratory for Functional and Metabolic Imaging (LIFMET), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6 CH F1 602 (Bâtiment CH), CH-1015 Lausanne, Switzerland===

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Abstract

The recent developments in high magnetic field 13C magnetic resonance spectroscopy with improved localization and shimming techniques have led to important gains in sensitivity and spectral resolution of 13C in vivo spectra in the rodent brain, enabling the separation of several 13C isotopomers of glutamate and glutamine. In this context, the assumptions used in spectral quantification might have a significant impact on the determination of the 13C concentrations and the related metabolic fluxes. In this study, the time domain spectral quantification algorithm AMARES (advanced method for accurate, robust and efficient spectral fitting) was applied to 13C magnetic resonance spectroscopy spectra acquired in the rat brain at 9.4 T, following infusion of [1,6-13C2] glucose. Using both Monte Carlo simulations and in vivo data, the goal of this work was: (1) to validate the quantification of in vivo 13C isotopomers using AMARES; (2) to assess the impact of the prior knowledge on the quantification of in vivo 13C isotopomers using AMARES; (3) to compare AMARES and LCModel (linear combination of model spectra) for the quantification of in vivo 13C spectra. AMARES led to accurate and reliable 13C spectral quantification similar to those obtained using LCModel, when the frequency shifts, J-coupling constants and phase patterns of the different 13C isotopomers were included as prior knowledge in the analysis. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

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