High-Resolution H-1-MRSI of the Brain Using SPICE: Data Acquisition and Image Reconstruction

作者：Lam Fan; Ma Chao; Clifford Bryan; Johnson Curtis L; Liang Zhi Pei^*

来源：Magnetic Resonance in Medicine, 2016, 76(4): 1059-1070.

DOI：10.1002/mrm.26019

• high-resolution spectroscopic imaging
• chemical shift imaging
• echo-planar spectroscopic imaging
• partial separability
• subspace model
• low-rank model
• brain imaging

Purpose: To develop data acquisition and image reconstruction methods to enable high-resolution H-1 MR spectroscopic imaging (MRSI) of the brain, using the recently proposed subspace-based spectroscopic imaging framework called SPICE (SPectroscopic Imaging by exploiting spatiospectral CorrElation).
Theory and Methods: SPICE is characterized by the use of a subspace model for both data acquisition and image reconstruction. For data acquisition, we propose a novel spatiospectral encoding scheme that provides hybrid data sets for determining the subspace structure and for image reconstruction using the subspace model. More specifically, we use a hybrid chemical shift imaging /echo-planar spectroscopic imaging sequence for two-dimensional (2D) MRSI and a dual-density, dual-speed echo-planar spectroscopic imaging sequence for three-dimensional (3D) MRSI. For image reconstruction, we propose a method that can determine the subspace structure and the high-resolution spatiospectral reconstruction from the hybrid data sets generated by the proposed sequences, incorporating field inhomogeneity correction and edge-preserving regularization.
Results: Phantom and in vivo brain experiments were performed to evaluate the performance of the proposed method. For 2D MRSI experiments, SPICE is able to produce high-SNR spatiospectral distributions with an approximately 3 mm nominal in-plane resolution from a 10-min acquisition. For 3D MRSI experiments, SPICE is able to achieve an approximately 3 mm in-plane and 4 mm through-plane resolution in about 25 min.
Conclusion: Special data acquisition and reconstruction methods have been developed for high-resolution H-1-MRSI of the brain using SPICE. Using these methods, SPICE is able to produce spatiospectral distributions of H-1 metabolites in the brain with high spatial resolution, while maintaining a good SNR. These capabilities should prove useful for practical applications of SPICE.

• 出版日期2016-10