Proton nuclear magnetic resonance imaging of acute experimental cerebral ischemia

To determine the efficacy of proton nuclear magnetic resonance (NMR) imaging in documenting acute ischemic infarction and to characterize the changes in these images during the first 24 hours following the ischemic insult, serial NMR imaging was performed in gerbils that had undergone unilateral carotid artery ligation. No significant changes in the signal intensity, T1 or T2 relaxation times were noted for either asymptomatic animals or the control hemisphere of symptomatic gerbils. There was a significant increase in T1 and especially T2 relaxation times and in both the relative signal intensity and Hf(v) for the ischemic hemisphere of symptomatic gerbils. These parameters appeared to increase linearly over 24 hours. The ischemic lesion first could be detected by NMR as early as 3 hours after carotid artery ligation, our earliest time point. The physiologic significance of these changes is discussed. These data suggest that NMR imaging may have significant diagnostic importance for acute cerebral ischemia and infarction in man.