Phosphorus MR spectroscopy: energetic metabolism and Warburg effect

Magnetic resonance spectroscopy (MRS) is a complementary imaging technique enabling non-invasive metabolic characterization of tissues in clinical practice. Proton MRS is more common for analysis of metabolites such as lactate and choline. This is valuable for preoperative assessment of glioma grade. However, it does not directly reflect phosphate energy metabolism. Phosphorus MRS enables assessment of phosphorus-containing compounds involved in tumor energy metabolism and membrane turnover. Objective. To assess the role of phosphorus MRS in metabolic characterization of low-grade and high-grade gliomas. Material and methods. The study included 46 patients with gliomas: 31 patients with high-grade gliomas and 15 patients with low-grade gliomas. The control group comprised 15 healthy volunteers. All participants underwent phosphorus MRS with assessment of spectral parameters of phosphorus-containing metabolites, metabolic ratios and intracellular pH. Results. Phosphorus MRS revealed differences in metabolic profile of tumor tissue between high-grade and low-grade gliomas. High-grade gliomas were characterized by signs of impaired energy and membrane metabolism, including changes in phosphorus-containing metabolite ratios and shift in intracellular pH. Low-grade gliomas demonstrated less severe metabolic alterations. Conclusion. Phosphorus MRS is a promising complementary imaging modality for non-invasive assessment of metabolic features of gliomas. This method may be used to refine their biological characteristics at the preoperative stage.