PT  - JOURNAL ARTICLE
AU  - Theresia Ziegs
AU  - Loreen Ruhm
AU  - Andrew Wright
AU  - Anke Henning
TI  - Mapping of Glutamate Metabolism using 1H FID-MRSI after oral Administration of [1-<sup>13</sup>C]Glc at 9.4 T
AID  - 10.1101/2022.09.05.506579
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.09.05.506579
4099  - http://biorxiv.org/content/early/2022/09/06/2022.09.05.506579.short
4100  - http://biorxiv.org/content/early/2022/09/06/2022.09.05.506579.full
AB  - Glutamate is the major excitatory transmitter in the brain and malfunction of the related metabolism is associated with various neurological diseases and disorders. The observation of labeling changes in the spectra after the administration of a 13C labelled tracer is a common tool to gain better insights into the function of the metabolic system. But so far, only a very few studies presenting the labelling effects in more than two voxels to show the spatial dependence of metabolism.In the present work, the labeling effects were measured in a transversal plane in the human brain using ultra-short TE and TR 1H FID-MRSI. The measurement set-up was most simple: The [1-13C]Glc was administered orally instead of intravenous and the spectra were measured with a pure 1H technique without the need of a 13C channel (as Boumezbeur et al. demonstrated in 2004). Thus, metabolic maps and enrichment curves could be obtained for more metabolites and in more voxels than ever before in human brain. Labeling changes could be observed in [4-13C]glutamate, [3-13C]glutamate+glutamine, [2-13C]glutamate+glutamine, [4-13C]glutamine, [2,3-13C]aspartate and [6-13C]N-acetyl aspartate with a high temporal (3.6 min) and spatial resolution (32×32 grid with nominal voxel size of 0.33 μL) in five volunteers.Competing Interest StatementThe authors have declared no competing interest.FIDfree induction decayTEecho timeTRrepetition timeMRSIMagnetic Resonance Spectroscopic ImagingGlcglucoseGluglutamateGlnglutamineAspAspartatePCpyruvate carboxylaseTCAtricarboxylic acid cyclePDHpyruvate dehydrogenase complexSVSsingle voxel spectroscopy