Quantification of individual magnetic resonance spectroscopy (MRS) signals is possible in the time domain using interactive nonlinear least-squares fitting methods which provide maximum likelihood parameter estimates under certain assumptions or using fully automatic, but statistically suboptimal, b
Quantification of magnetic resonance spectroscopy signals with lineshape estimation
β Scribed by M. I. Osorio-Garcia; D. M. Sima; F. U. Nielsen; U. Himmelreich; S. Van Huffel
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 949 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0886-9383
- DOI
- 10.1002/cem.1353
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β¦ Synopsis
Abstract
Quantification of magnetic resonance spectroscopy (MRS) signals is required for providing metabolite concentrations of the tissue under investigation. For estimating these concentrations several biochemical and acquisition conditions need to be taken into account. It is still a challenge to obtain reliable concentrations, as experimental conditions may have a detrimental effect on the spectral quality. The lineshape of MRS signals is affected, for instance, by inhomogeneities of the static magnetic field arising from imperfect shimming and tissue heterogeneities. To handle this type of distortions, we propose an extension of the selfβdeconvolution method, where a common lineshape is estimated and a robust method with local regression is included to improve the smoothing of the estimated damping (or lineshape) function. This common lineshape is imposed in the metabolite quantification method and the spectral parameters (amplitude, frequency, damping and phase corrections) are obtained via nonlinear least squares. In this study, we considered distorted simulated, in vitro and in vivo rat brain signals which were lineshape corrected and quantitative results were compared in all three cases. Copyright Β© 2011 John Wiley & Sons, Ltd.
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