Persistent high lactate level as a sensitive MR spectroscopy indicator of completed infarction.

Serial proton (1H) and phosphorus-31 (31P) magnetic resonance (MR) spectroscopy of cerebral infarction was performed in rats to assess the sensitivity of these techniques for use in clinical cerebral infarction. In this experimental chronic infarction model, 31P spectroscopy tended to return to a "normal" pattern within 24 hours after induction of infarction in spite of pathologically proven completed infarction and, therefore, appeared not to be sensitive enough for clinical application. On the other hand, proton spectroscopy invariably showed persistent high lactate levels and was capable of distinguishing completed infarction from reperfused recovered brain. Persistent high lactate levels appear to be a good MR spectroscopic indicator of completed infarction.