title: High and ultra-high resolution metabolite mapping of the human brain using1H FID MRSI at 9.4T.
abstract: Magnetic resonance spectroscopic imaging (MRSI) is a promising technique for mapping the spatial distribution of multiple metabolites in the human brain. These metabolite maps can be used as a diagnostic tool to gain insight into several biochemical processes and diseases in the brain. In comparison to lower field strengths, MRSI at ultra-high field strengths benefits from a higher signal to noise ratio (SNR) as well as higher chemical shift dispersion, and hence spectral resolution. This study combines the benefits of an ultra-high field magnet with the advantages of an ultra-short TE and TR single-slice FID-MRSI sequence (such as negligible J-evolution and loss of SNR due to T2relaxation effects) and presents the first metabolite maps acquired at 9.4T in the healthy human brain at both high (voxel size of 97.6µL) and ultra-high (voxel size of 24.4µL) spatial resolutions in a scan time of 11 and 46min respectively. In comparison to lower field strengths, more anatomically-detailed maps with higher SNR from a larger number of metabolites are shown. A total of 12 metabolites including glutamate (Glu), glutamine (Gln), N-acetyl-aspartyl-glutamate (NAAG), Gamma-aminobutyric acid (GABA) and glutathione (GSH) are reliably mapped. Comprehensive description of the methodology behind these maps is provided.
authors.affiliation: Max Planck Institute for Biological Cybernetics, Spemannstr. 41, Tuebingen 72076, Germany; IMPRS for Cognitive and Systems Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany. Electronic address: sahar.nassirpour@tuebingen.mpg.de.
authors.forename: Sahar
authors.initials: S
authors.lastname: Nassirpour
authors.affiliation: Max Planck Institute for Biological Cybernetics, Spemannstr. 41, Tuebingen 72076, Germany; IMPRS for Cognitive and Systems Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Chang
authors.affiliation: Max Planck Institute for Biological Cybernetics, Spemannstr. 41, Tuebingen 72076, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Henning
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D059906:Neuroimaging / Q000379:methods*; D066244:Proton Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*
keywords: 9.4T; FID MRSI; Human brain; Metabolite mapping; Spectroscopic imaging; Ultra-high magnetic field