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Influence of measured and simulated basis sets on metabolite concentration estimates
Author(s) -
Cudalbu Cristina,
Cavassila Sophie,
Rabeson Herald,
van Ormondt Dirk,
GraveronDemilly Danielle
Publication year - 2008
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1234
Subject(s) - metabolite , basis (linear algebra) , monte carlo method , set (abstract data type) , basis set , basis function , biological system , mathematics , statistics , computer science , chemistry , biology , computational chemistry , mathematical analysis , density functional theory , biochemistry , geometry , programming language
By quantification of brain metabolites, localized brain proton MRS can non‐invasively provide biochemical information from distinct regions of the brain. Quantification of short‐ TE signals is usually based on a metabolite basis set. The basis set can be obtained by two approaches: (1) by measuring the signals of metabolites in aqueous solution; (2) by quantum‐mechanically simulating the theoretical metabolite signals. The purpose of this study was to compare the effect of these two approaches on metabolite concentration estimates. Metabolite concentrations were quantified with the QUEST method, using both approaches. A comparison was performed with the aid of Monte Carlo studies, by using signals simulated from both basis sets. The best results were obtained when the basis set used for the fit was the same as that used to simulate the Monte Carlo signals. This comparison was also performed using in vivo short‐ TE signals acquired at 7 T from the central region of rat brains. The concentration estimates, with confidence intervals, obtained using both basis sets were in good agreement with values from the literature. The in vivo study showed that, in general, the differences between the estimates obtained with the two basis sets were not statistically significant or scientifically important. Consequently, a simulated basis set can be used in place of a measured basis set. Copyright © 2007 John Wiley & Sons, Ltd.