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Advanced parallel magnetic resonance imaging methods with applications to MR spectroscopic imaging

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Please use this identifier to cite or link to this item: http://hdl.handle.net/1928/3610

Advanced parallel magnetic resonance imaging methods with applications to MR spectroscopic imaging

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Title: Advanced parallel magnetic resonance imaging methods with applications to MR spectroscopic imaging
Author: Otazo, Ricardo
Advisor(s): Posse, Stefan
Jordan, Ramiro
Committee Member(s): Pattichis, Marios
Caprihan, Arvind
Department: University of New Mexico. Dept. of Electrical and Computer Engineering
Subject(s): magnetic resonance imaging
parallel imaging
inverse reconstruction
superresolution
LC Subject(s): Brain--Magnetic resonance imaging
Magnetic resonance imaging.
Spectroscopic imaging.
Magnetic resonance imaging.
Degree Level: Doctoral
Abstract: Parallel magnetic resonance imaging offers a framework for acceleration of conventional MRI encoding using an array of receiver coils with spatially-varying sensitivities. Novel encoding and reconstruction techniques for parallel MRI are investigated in this dissertation. The main goal is to improve the actual reconstruction methods and to develop new approaches for massively parallel MRI systems that take advantage of the higher information content provided by the large number of small receivers. A generalized forward model and inverse reconstruction with regularization for parallel MRI with arbitrary k-space sub-sampling is developed. Regularization methods using the singular value decomposition of the encoding matrix and pre-conditioning of the forward model are proposed to desensitize the solution from data noise and model errors. Variable density k-space sub-sampling is presented to improve the reconstruction with the common uniform sub-sampling. A novel method for massively parallel MRI systems named Superresolution Sensitivity Encoding (SURE-SENSE) is proposed where acceleration is performed by acquiring the low spatial resolution representation of the object being imaged and the stronger sensitivity variation from small receiver coils is used to perform intra-pixel reconstruction. SURE-SENSE compares favorably the performance of standard SENSE reconstruction for low spatial resolution imaging such as spectroscopic imaging. The methods developed in this dissertation are applied to Proton Echo Planar Spectroscopic Imaging (PEPSI) for metabolic imaging in human brain with high spatial and spectral resolution in clinically feasible acquisition times. The contributions presented in this dissertation are expected to provide methods that substantially enhance the utility of parallel MRI for clinical research and to offer a framework for fast MRSI of human brain with high spatial and spectral resolution.
Graduation Date: December 2007
URI: http://hdl.handle.net/1928/3610

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