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Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging
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Fast Chemical Shift Encoded and J-Decoupled/J-Resolved MRSI Based on Cross-Term Spatiotemporal Encoding
Ke Dai1, Xinjie Liu2, Yiling Liu1
1National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
NMR in Biomedicine
|September 15, 2025
Summary
This study introduces t1-xSPEN spectroscopic imaging, a faster MRI method for brain metabolite mapping. It overcomes limitations of previous techniques, improving diagnosis of neurological disorders.
Area of Science:
- Medical Imaging
- Neuroscience
- Spectroscopy
Background:
- Magnetic resonance spectroscopic imaging (MRSI) is vital for noninvasive brain metabolite analysis but suffers from long acquisition times.
- Echo-planar spectroscopic imaging (EPSI) improved speed but has spectral bandwidth and field inhomogeneity limitations.
- Cross-term spatiotemporal encoding (xSPEN) offers resistance to chemical shifts and field inhomogeneities.
Purpose of the Study:
- To extend xSPEN for enhanced MRSI acquisition efficiency and spectral bandwidth flexibility.
- To develop a J-decoupled xSPEN technique for improved metabolite mapping.
- To integrate t1-xSPEN with turbo spin echo for robust J-coupling information acquisition.
Main Methods:
- Developed t1-xSPEN spectroscopic imaging by incorporating t1 evolution into echo-planar imaging-based xSPEN.
- Implemented J-decoupling by splitting t1 evolution around a pi pulse for constant tau J-coupling.
- Combined t1-xSPEN with turbo spin echo train acquisition.
Main Results:
- Achieved enhanced sampling efficiency and flexible spectral bandwidth, surpassing EPSI limitations.
- Enabled J-decoupled xSPEN spectroscopic imaging with constant tau J-coupling.
- Demonstrated robust, distortion-free acquisition of J-coupling information.
Conclusions:
- t1-xSPEN spectroscopic imaging offers improved resolution and accuracy for brain metabolite mapping.
- The technique provides new insights for diagnosing and understanding neurological disorders.
- This advanced MRSI method enhances noninvasive analysis of brain pathologies.
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