PROTON MR SPECTROSCOPY OF EXPERIMENTAL BRAIN-TUMORS IN-VIVO

F98 gliomas, E367 neuroblastomas, and RN6 Schwannomas in rat brain wer e studied non-invasively in vivo by localized proton MR spectroscopy ( MRS). The spectra obtained from homotopic brain contralateral to the t umors were qualitatively indistinguishable from those of normal rat br ain in vivo and showed-resonance lines assigned to N-acetylaspartate, glutamate, total creatine (creatine and phosphocreatine), choline, glu cose, and myo-inositol. The tumor spectra displayed marked differences compared to those obtained from contralateral brain. There were incre ases in choline, myo-inositol and lipids, which are presumably associa ted with increased membrane turnover. The presence of lactate indicate d anaerobic glycolysis. Other differences included the absence of sign als from NAA resulting from the destruction or displacement of neurona l tissue by the tumor. There was also a loss of total creatine. Althou gh the spectra of all three tumor types were distinct from contralater al brain, there were no obvious differences between the different tumo r types.