Characterization of choline compounds with in vitro 1H magnetic resonance spectroscopy for the discrimination of primary brain tumors

RATIONALE AND OBJECTIVES. The authors sought to compare H-1 magnetic resonance spectroscopy (MRS) spectra from extracts of low-grade and high-grade gliomas, especially with respect to the signals of choline-containing compounds. METHODS. Perchloric acid extracts of six high-grade and six low-grade gliomas were analyzed by H-1 MRS at 9.4 Tesla. RESULTS. The signals of glycerophosphocholine (GPC) at 3.23 ppm, phosphocholine (PC) at 3.22 ppm, and choline (Cho) at 3.21 ppm were identified in both types of tumors. The absolute concentrations of all Cho-containing compounds (GPC + PC + Cho) in high-grade and low-grade gliomas were significantly different. The relative contributions of each of the Cho-containing compounds to the total choline signal were also statistically different. For high-grade gliomas, the choline signal is composed of GPC, PC, and Cho in a well-balanced contribution, whereas in low-grade gliomas, the signal is largely due to GPC with a small involvement of PC and Cho. CONCLUSIONS. The differences in the concentration and the repartition of Cho-containing compounds seem to be a marker of high-grade gliomas, They could also help to discriminate between high- and low-grade gliomas in some difficult cases.