[Proton and phosphorus-31 nuclear magnetic resonance spectroscopy in experimental cerebral infarction in rats]

Longitudinal study of metabolic change after cerebral infarction was done using nuclear magnetic resonance spectroscopy (MRS). Localized completed infarction model induced by intra-cranial ligation of the middle cerebral artery and extra-cranial ligation of common carotid artery in rats was utilized. In acute study the proton MRS revealed a sharp increase of lactic acid but the phosphorus -31 MRS did not show prominent changes. This increase of lactic acid persists 24 hours after the induction of infarction. In chronic study the spectroscopic pattern of the infarcted brain showed minimum difference from the control normal brain. However the signal intensity of phosphomonoester was significantly higher in the infarcted brain. Our study in acute phase suggests that the proton MRS is a sensitive probe to detect an early metabolic deterioration induced by ischemic insult. And the increase of phosphomonoester in chronic infarcted brain may imply that a gliosis seen in chronic infarction has a metabolic resemblance to neonate brain and neoplasm.