Automatic quantitation of localized in vivo 1H spectra with LCModel
TLDR
The LCModel method analyzes an in vivo spectrum as a Linear Combination of Model in vitro spectra from individual metabolite solutions using complete model spectra, rather than individual resonances, in order to incorporate maximum prior information into the analysis.Abstract:
The LCModel method analyzes an in vivo spectrum as a Linear Combination of Model in vitro spectra from individual metabolite solutions. Complete model spectra, rather than individual resonances, are used in order to incorporate maximum prior information into the analysis. A nearly model-free constrained regularization method automatically accounts for the baseline and lineshape in vivo without imposing a restrictive parameterized form on them. LCModel is automatic (non-interactive) with no subjective input. Approximately maximum-likelihood estimates of the metabolite concentrations and their uncertainties (Cramer-Rao lower bounds) are obtained. LCModel analyses of spectra from users with fields from 1.5 to 9.4 T and a wide range of sequences, particularly with short TE, are used here to illustrate the capabilities and limitations of LCModel and proton MRS.read more
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References
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Journal ArticleDOI
Estimation of metabolite concentrations from localized in vivo proton NMR spectra
TL;DR: The LCModel method analyzes an in vivo spectrum as a Linear Combination of Model spectra of metabolite solutions in vitro by using complete model spectra, rather than just individual resonances, to ensure maximum information and uniqueness are incorporated into the analysis.
Journal ArticleDOI
A constrained regularization method for inverting data represented by linear algebraic or integral equations
TL;DR: CONTIN as discussed by the authors is a portable Fortran IV package for inverting noisy linear operator equations, which can be used for the analysis of data from a wide variety of experiments, including photon correlation spectroscopy, multicomponent spectra, and Fourier-Bessel, Fourier and Laplace transforms.
Journal ArticleDOI
Toward an in Vivo Neurochemical Profile: Quantification of 18 Metabolites in Short-Echo-Time 1H NMR Spectra of the Rat Brain
TL;DR: Frequency domain analysis with LCModel showed that the in vivo spectra can be explained by 18 metabolite model solution spectra and a highly structured background, which was attributed to resonances with fivefold shorter in vivo T(1) than metabolites.
Journal ArticleDOI
Regional metabolite concentrations in human brain as determined by quantitative localized proton MRS.
Petra J. W. Pouwels,Jens Frahm +1 more
TL;DR: The present findings neither support a metabolic gender difference (except for a 1.3‐fold higher myo‐inositol level in parietal white matter of female subjects) nor a metabolic hemispheric asymmetry.
Journal ArticleDOI
Dynamic uncoupling and recoupling of perfusion and oxidative metabolism during focal brain activation in man.
TL;DR: Initial nonoxidative glucose consumption during functional activation is gradually complemented by a slower adjustment of oxidative phosphorylation that „recouples” perfusion and oxygen consumption at a new equilibrium.