Band-Selective IR PRESS for Brain Tumor Spectroscopy Allows Robust Detection of Lactate

Area of Science:

• Biophysics
• Biochemistry
• Medical Imaging

Background:

• Lactate is crucial in the tumor microenvironment, influencing progression, metastasis, and immune evasion.
• In vivo lactate quantification via magnetic resonance spectroscopy (MRS) is challenging due to overlapping lipid signals.
• Conventional long echo time MRS suppresses essential metabolite signals while attempting to differentiate lactate from lipids.

Purpose of the Study:

• To develop an improved MRS method for accurate in vivo lactate quantification.
• To overcome the limitations of current MRS techniques in distinguishing lactate from lipid signals.
• To enable comprehensive metabolite profiling in the tumor microenvironment.

Main Methods:

• Introduction of a novel selective inversion pulse with a short echo time MRS method (SPIR-PRESS).
• Utilized differences in T1 relaxation times between lactate and lipids.
• Validated the method using phantom experiments and a mouse glioma model.

Main Results:

• SPIR-PRESS effectively suppressed interfering lipid signals in short echo time PRESS spectra.
• The new method maintained sensitivity to the complete metabolite profile.
• SPIR-PRESS showed a ~60% increase in lactate detection sensitivity compared to conventional long echo time PRESS.
• SPIR-PRESS detected key tumor metabolites (lactate, total choline, creatine, NAA) in a mouse glioma model, which were undetectable with conventional MRS.

Conclusions:

• SPIR-PRESS is a promising MRS technique for enhanced lactate quantification in tumors.
• The method allows for more comprehensive metabolite profiling within the tumor microenvironment.
• SPIR-PRESS offers superior performance over conventional MRS for studying lactate's role in cancer.