Accelerating phase-encoded proton MR spectroscopic imaging by compressed sensing

Abstract

© 2014 Wiley Periodicals, Inc. Purpose: To develop a phase encoding reduction scheme based on compressed sensing (CS) for phase-encoded 1H MR spectroscopic imaging (MRSI). Materials and Methods: Phantom and in vivo rat brain MRSI experiments were performed at 7 Tesla to examine the performance of CS approach and compare it with the full k-space acquisition. The CS undersampling was performed by acquiring a pseudorandom and density-varying subset of phase encodings. Residual water resonance was first removed from the undersampled k-space dataset before CS reconstruction. The CS reconstruction was performed by a linearized Bregman iteration procedure for efficiency in computing large scale L1 minimization. The spectral and spatial fidelity was evaluated by comparing spectral linewidths and metabolite maps and voxel-wise Bland-Altman analysis. Results: CS preserved the spectral resolution and metabolite content levels. No spectral broadening was observed, and the estimation biases of the metabolite content levels were no more than 4%. CS clearly preserved the boundaries of metabolite maps but led to slight loss of details in metabolite maps. Conclusion: This study demonstrated the feasibility of the proposed CS approach to accelerate phase-encoded 1H MRSI.