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Trace apparent diffusion coefficients of metabolites in human brain using diffusion weighted magnetic resonance spectroscopy
Author(s) -
Ellegood Jacob,
Hanstock Chris C.,
Beaulieu Christian
Publication year - 2005
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20427
Subject(s) - nuclear magnetic resonance , white matter , phosphocreatine , chemistry , diffusion mri , human brain , creatine , fractional anisotropy , effective diffusion coefficient , nuclear magnetic resonance spectroscopy , analytical chemistry (journal) , physics , magnetic resonance imaging , neuroscience , biology , medicine , biochemistry , chromatography , radiology , endocrinology , energy metabolism
The rotationally invariant trace/3 apparent diffusion coefficients (ADC) of N ‐acetyl aspartate (NAA), creatine and phosphocreatine (tCr), and choline (Cho) were determined using a diffusion‐weighted stimulated echo acquisition mode sequence at 3 T in three separate human brain regions, namely the subcortical white matter, occipital gray matter, and frontal gray matter. The measurement of the mean diffusivity eliminates the dependence of the measured ADC on the direction of the diffusion gradient relative to the tissue microstructure (i.e., anisotropy). Macroscopic brain motions induce phase errors that were compensated for by phasing (zero and first order) on the single average spectrum (zero order on the NAA peak) prior to summing the individual spectra. This method yielded reproducible trace/3 ADC values in the expected range without the use of cardiac gating. The mean diffusivity of NAA (0.14 ± 0.03 × 10 −3 mm 2 /s) appears to be less than that of tCr (0.17 ± 0.04 × 10 −3 mm 2 /s) and Cho (0.18 ± 0.05 × 10 −3 mm 2 /s) in human brain. Magn Reson Med 53:1025–1032, 2005. © 2005 Wiley‐Liss, Inc.