Human brain glucose metabolism mapping using multislice 2D (1)H-(13)C correlation HSQC spectroscopy

Area of Science:

• Neuroimaging
• Metabolic Spectroscopy
• Magnetic Resonance Imaging

Background:

• Human brain metabolism studies are crucial for understanding neurological function and disease.
• Conventional Magnetic Resonance Spectroscopy (MRS) methods have limitations in temporal resolution and specificity for metabolic tracking.
• In vivo monitoring of metabolic pathways requires advanced spectroscopic techniques.

Purpose of the Study:

• To develop and validate a novel multivolume 2D (1)H-(13)C correlation spectroscopy method, multislice heteronuclear single quantum coherence (HSQC).
• To enable the tracking of human brain metabolism, specifically the conversion of glucose to amino acids, using a whole-body scanner.
• To achieve improved temporal resolution for metabolic studies in the human brain.

Main Methods:

• Modified heteronuclear single quantum coherence (HSQC) pulse sequence with separated (13)C and (1)H 180-degree pulses in the preparation period.
• Application of a 180-degree (13)C pulse at 1/(4J(CH)) before the 90-degree (1)H polarization transfer (PT) pulse.
• Utilizing multislice 90-degree (1)H reverse PT pulses for enhanced spatial coverage and slice selection in a whole-body scanner.

Main Results:

• The developed multislice HSQC method allowed for the time-course monitoring of glutamate C4.
• A temporal resolution of 15 minutes was achieved for tracking metabolic changes.
• Spectra were obtained from the brains of volunteers after oral administration of 13C-labeled glucose, with a maximum signal-to-noise ratio (S/N) of 3.

Conclusions:

• The proposed multislice HSQC technique is feasible for in vivo human brain metabolism studies.
• This method facilitates the dynamic follow-up of metabolic pathways from glucose to amino acids.
• The technique offers a promising approach for non-invasive metabolic investigations in neurological research using whole-body MRI systems.