Mapping of the brain from water-unsuppressed 1 H-MRSIand turbo spin-echo data.

Abstract

To obtain high-quality maps of brain tissues from water-unsuppressed magnetic resonance spectroscopic imaging (MRSI)and turbo spin-echo (TSE) data. mapping can be achieved using mapping from water-unsuppressed MRSI data and mapping from TSE data. However, mapping often suffers from signal dephasing and distortions caused by field inhomogeneity; measurements may be biased due to system imperfections, especially for -weighted image with small number of TEs. In this work, we corrected the field inhomogeneity effect on mapping using a subspace model-based method, incorporating pre-learned spectral basis functions of the water signals. estimation bias was corrected using a TE-adjustment method, which modeled the deviation between measured and reference decays as TE shifts. In vivo experiments were performed to evaluate the performance of the proposed method. High-quality maps were obtained in the presence of large field inhomogeneity in the prefrontal cortex. Bias in measurements obtained from TSE data was effectively reduced. Based on the and measurements produced by the proposed method, high-quality maps were obtained, along with neurometabolite maps, from MRSI and TSE data that were acquired in about 9min. The results obtained from acute stroke and glioma patients demonstrated the feasibility of the proposed method in the clinical setting. High-quality maps can be obtained from water-unsuppressed 1 H-MRSI and TSE data using the proposed method. With further development, this method may lay a foundation for simultaneously imaging oxygenation and neurometabolic alterations of brain disorders.