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Diffusion‐weighted spectroscopy: A novel approach to determine macromolecule resonances in short‐echo time 1 H‐MRS
Author(s) -
Kunz N.,
Cudalbu C.,
Mlynarik V.,
Hüppi P. S.,
Sizonenko S. V.,
Gruetter R.
Publication year - 2010
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.22490
Subject(s) - metabolite , nuclear magnetic resonance , chemistry , neurochemical , spectroscopy , spin echo , nuclear magnetic resonance spectroscopy , echo time , creatine , analytical chemistry (journal) , magnetic resonance imaging , physics , chromatography , biochemistry , biology , medicine , endocrinology , radiology , quantum mechanics
Quantification of short‐echo time proton magnetic resonance spectroscopy results in >18 metabolite concentrations (neurochemical profile). Their quantification accuracy depends on the assessment of the contribution of macromolecule (MM) resonances, previously experimentally achieved by exploiting the several fold difference in T 1 . To minimize effects of heterogeneities in metabolites T 1 , the aim of the study was to assess MM signal contributions by combining inversion recovery (IR) and diffusion‐weighted proton spectroscopy at high‐magnetic field (14.1 T) and short echo time (=8 msec) in the rat brain. IR combined with diffusion weighting experiments (with δ/Δ = 1.5/200 msec and b ‐value = 11.8 msec/μm 2 ) showed that the metabolite nulled spectrum (inversion time = 740 msec) was affected by residuals attributed to creatine, inositol, taurine, choline, N ‐acetylaspartate as well as glutamine and glutamate. While the metabolite residuals were significantly attenuated by 50%, the MM signals were almost not affected (<8%). The combination of metabolite‐nulled IR spectra with diffusion weighting allows a specific characterization of MM resonances with minimal metabolite signal contributions and is expected to lead to a more precise quantification of the neurochemical profile. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.