L-glutamine as a T₂ exchange contrast agent.

Area of Science:

• Biophysics
• Medical Imaging
• Biochemistry

Background:

• Magnetic Resonance Imaging (MRI) relies on contrast agents to enhance image clarity.
• Investigating novel agents like L-glutamine can expand MRI's diagnostic capabilities.
• Understanding amino acid metabolism is crucial for cancer research.

Purpose of the Study:

• To evaluate L-glutamine as a T2 exchange contrast agent in MRI.
• To assess the feasibility of imaging L-glutamine uptake in vivo.

Main Methods:

• Measured T2 relaxation rates of L-glutamine solutions at various concentrations and 9.4 T.
• Acquired T2-weighted MRI images in a mouse cancer model following L-glutamine infusion.
• Quantified T2 relaxivity (R2ex) attributed to exchange processes.

Main Results:

• L-glutamine exhibited T2 relaxivity (R2ex) of 0.069 s⁻¹ mM⁻¹ at 37°C and pH 7.2.
• Glutamine R2ex values ranged from 0.097-0.1 s⁻¹ mM⁻¹ at pH 6.1-6.7.
• In vivo MRI demonstrated localized glutamine uptake within tumors.

Conclusions:

• L-glutamine functions effectively as a T2 exchange contrast agent.
• MRI can successfully visualize L-glutamine uptake in living organisms.
• This technique holds promise for studying tumor metabolism and drug delivery.