Image-guided localized 31P-MRS study of human brain tumors and cerebrovascular disease

The purpose of this study was to evaluate the energy metabolism of human brain tumors and cerebrovascular diseases using both 1H-MRI and volume-selected 31P-MRS. The subjects were 15 untreated patients with brain tumors - comprising glioblastoma (4), benign glioma (one), meningioma (5), neurinoma (4), and metastasis (one) - and one patient with intracerebral hematoma. Twelve healthy volunteers served as controls. The group of glioma patients had a decreased signal for phosphocreatine (Pcr) and an increased signal for phosphomonoesters (PME). The degree of changes in these signals varied from patient to patient. In the group of meningioma patients, the spectra showed a significant decrease in the Pcr signal and a decrease in the S/N ratio of all signals, compared with normal brain tissues. A patient with metastatic tumor from the lung had 31P-MR spectra specific to the tumor, including a marked increase in the PME signal and a decrease in the Pcr signal. In the case of intracerebral hematoma, the 31P-MR spectrum showed each signal to have decreased, while the signal for inorganic phosphate had increased compared with those of the contralateral hemisphera. In conclusion, the 31P-MR spectra of human brain tumors were characterized by having a decreased total content of high energy phosphorus compounds, compared with normal brain tissue; a decreased Pcr signal, and a peak height of the PME signal which varied with the type of tumor. (Namekawa, K)