A Glycine-Targeted In Vivo Magnetic Resonance Spectroscopy for Quantifying Glycine in Glioma

Area of Science:

• Biomedical Engineering
• Neuro-oncology
• Metabolic Imaging

Background:

• Glycine (Gly) is crucial for tumor cell proliferation, making its concentration monitoring vital for assessing tumor growth.
• Conventional magnetic resonance spectroscopy (MRS) struggles to accurately measure Gly in human tissues due to overlapping ¹H signals from other molecules.

Purpose of the Study:

• To develop a novel pulse sequence, Gly-MRS, for precise in vivo quantification of Gly concentrations in human gliomas.
• To overcome the challenge of overlapping signals that hinders accurate Gly measurement in conventional MRS.

Main Methods:

• A prospective study utilizing a 3 Tesla scanner and a Gly-targeted MRS pulse sequence (Gly-MRS) with Point-RESolved Spectroscopy (PRESS).
• Testing was performed on phantoms and 6 human glioma subjects (3 female, 3 male, BMI 20±4 kg/m², age 50±10 years).

Main Results:

• The Gly-MRS sequence successfully and selectively detected ¹H signals of Gly in glioma phantoms and patients.
• In 6 glioma subjects, Gly concentrations in tumor regions averaged 5.20 ± 3.29 mM, with one subject showing distinct spatial distribution.

Conclusions:

• The developed Gly-MRS pulse sequence enables accurate in vivo detection of ¹H signals of Gly in human gliomas.
• This technique holds promise for improved non-invasive monitoring of glycine metabolism in brain tumors.