Proton MR spectroscopic imaging of human glioblastomas at 1.5 Tesla

In this study we evaluated clinical feasibility of proton magnetic resonance spectroscopy metabolite mapping (1H MRSI) by using 1.5 Tesla MR-scanner in 10 patients with high-grade glioblastoma. In vivo 1H MRSI performed with a relatively short scan time of 20 minutes enabled to obtain comprehensive information about metabolic changes in glioblastoma and adjacent tissues namely in the peritumoral edema, in the middle and solid part of the tumor, and in the normal-appearing brain tissue. Spectroscopically it was possible to identify initiation of neuronal cell death in the solid tumorous tissue via decreased N-acetyl-aspartate to creatine ratio (↓ tNAA/tCr) and expanding carcinogenesis reflected in elevated choline ratios (↑ tCho/tCr and tCho/tNAA). We showed also the central necrosis of glioblastoma accompanied by the tissue hypoxia, which were apparent as increased lactate and lipids ratios (↑ Lac/tCr and lip/Lac). Metabolic changes were noticeable also in the peritumoral area, showing the glioblastoma infiltration into the surrounding tissues. In intracranial tumors, 1H MRSI performed on 1.5 Tesla field strength was sufficient to provide information about the stage of carcinogenesis, tumor expansion or necrotization and thus it could be considered as a useful diagnostic tool in oncology.