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Improved model-based magnetic resonance spectroscopic imaging
Journal article   Peer reviewed

Improved model-based magnetic resonance spectroscopic imaging

Mathews Jacob, Xiaoping Zhu, Andreas Ebel, Norbert Schuff and Zhi-Pei Liang
IEEE transactions on medical imaging, Vol.26(10), pp.1305-1318
10/2007
DOI: 10.1109/TMI.2007.898583
PMID: 17948722

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Abstract

Model-based techniques have the potential to reduce the artifacts and improve resolution in magnetic resonance spectroscopic imaging, without sacrificing the signal-to-noise ratio. However, the current approaches have a few drawbacks that limit their performance in practical applications. Specifically, the classical schemes use less flexible image models that lead to model misfit, thus resulting in artifacts. Moreover, the performance of the current approaches is negatively affected by the magnetic field inhomogeneity and spatial mismatch between the anatomical references and spectroscopic imaging data. In this paper, we propose efficient solutions to overcome these problems. We introduce a more flexible image model that represents the signal as a linear combination of compartmental and local basis functions. The former set represents the signal variations within the compartments, while the latter captures the local perturbations resulting from lesions or segmentation errors. Since the combined set is redundant, we obtain the reconstructions using sparsity penalized optimization. To compensate for the artifacts resulting from field inhomogeneity, we estimate the field map using alternate scans and use it in the reconstruction. We model the spatial mismatch as an affine transformation, whose parameters are estimated from the spectroscopy data.
Reproducibility of Results Magnetic Resonance Spectroscopy - methods Brain - anatomy & histology Humans Image Interpretation, Computer-Assisted - methods Magnetic Resonance Imaging - methods Brain - metabolism Tissue Distribution Algorithms Computer Simulation Sensitivity and Specificity Image Enhancement - methods Models, Neurological Lipid Metabolism - physiology

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