In Vivo Measurement of Taurine With Optimized Double-Quantum Filtering Magnetic Resonance Spectroscopy

Area of Science:

• Neuroimaging
• Metabolomics
• Magnetic Resonance Spectroscopy

Background:

• Taurine is a crucial metabolite in the brain, involved in various physiological processes.
• Accurate in vivo quantification of taurine is essential for understanding neurological conditions.
• Current quantification methods, including conventional MRS and non-optimized DQF, have limitations in accuracy and reproducibility.

Purpose of the Study:

• To enhance the accuracy and reproducibility of in vivo taurine quantification using an optimized double-quantum filtering (DQF) technique.
• To determine optimal parameters for DQF at 7 Tesla (7T) and 3 Tesla (3T) for maximizing taurine signal purity and minimizing interference.
• To validate the optimized DQF method in animal models and human studies.

Main Methods:

• Simulations and phantom experiments were performed at 7T and 3T to identify optimal DQF parameters (τ, pulse bandwidth, gradient moments).
• The optimized DQF sequence was applied to rat models of C6 gliomas and compared to normal brain tissue at 7T.
• Metabolomics was used for validation, and human gray and white matter taurine differences were assessed at 3T, with test-retest reliability evaluated.

Main Results:

• Optimal τ values of 102 ms (7T) and 92 ms (3T) were identified, maximizing taurine signal purity.
• Optimized DQF sequences demonstrated lower Cramer-Rao Lower Bounds (CRLB) and reduced water side band interference.
• In rat brains, optimized DQF showed strong correlation with metabolomics, outperforming conventional MRS and non-optimized DQF.
• The optimized method revealed significant taurine differences between gray and white matter in humans and exhibited good test-retest reproducibility (ICC = 0.82) in gray matter.

Conclusions:

• The optimized DQF method significantly enhances taurine detection accuracy and robustness in both animal and human studies.
• This optimized DQF technique represents a significant advancement for in vivo taurine quantification.
• The study successfully applied the optimized DQF method for human brain taurine testing at 3T for the first time.