title: Differences in apparent diffusion coefficients of brain metabolites between grey and white matter in the human brain measured at 7 T.
abstract: Diffusion weighted spectroscopy can provide microstructural information that is specific to compartmental geometry. So far, in human brain, apparent diffusion coefficients (ADCs) of only the metabolites N-acetyl aspartate, creatine (tCr) and choline (tCho) have been assessed. High field MR at 7 T allows the collection and analysis of diffusion weighted spectroscopy data of additional metabolites of interest such as glutamate (Glu), N-acetyl aspartyl glutamate, and glutamine (Gln), which are of interest due to their different compartmentalization and role in brain physiology. In this study, we performed (1)H diffusion weighted spectroscopy at 7 T using a diffusion-weighted PRESS sequence in parietal white matter (n = 6) and occipital grey matter (n = 7). Data were analyzed using the LCmodel. ADCs could reliably be obtained of N-acetyl aspartate, tCr, tCho, Glu, Gln in grey and white matter, and N-acetyl aspartyl glutamate in white matter. Significant differences in ADC values were observed between grey and white matter for all metabolites. ADCs in grey matter were consistently lower than in white matter. These differences can probably be attributed to different compartmentalization as well as to the differential impact of diffusion time on ADC of different molecules under conditions of restricted diffusion.
authors.affiliation: CJ Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. h.e.kan@lumc.nl
authors.forename: Hermien E
authors.initials: HE
authors.lastname: Kan
authors.forename: Aranee
authors.initials: A
authors.lastname: Techawiboonwong
authors.forename: Matthias J P
authors.initials: MJ
authors.lastname: van Osch
authors.forename: Maarten J
authors.initials: MJ
authors.lastname: Versluis
authors.forename: Dinesh K
authors.initials: DK
authors.lastname: Deelchand
authors.forename: Pierre-Gilles
authors.initials: PG
authors.lastname: Henry
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Marjańska
authors.forename: Mark A
authors.initials: MA
authors.lastname: van Buchem
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Webb
authors.forename: Itamar
authors.initials: I
authors.lastname: Ronen
mesh_terms: D000465:Algorithms; D001921:Brain / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009413:Nerve Fibers, Myelinated / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*