BACKGROUND: The plasma level of neuron specific enolase (NSE) can be used to diagnose and evaluate neuronal injury and predict early prognosis.OBJECTIVE: To observe the dynamic changes in plasma levels of NSE in patients with acute cerebral infarction, and to investigate its correlations with disease severity and prognosis.DESIGN, TIME AND SETTING: This non-randomized, concurrent case-control experiment was performed at the Department of Neurology, First Hospital Affiliated to Heilongjiang University of Traditional Chinese Medicine between May and July 2007.PARTICIPANTS: Eighteen patients with acute cerebral infarction, who received treatment at the Department of Neurology, First Hospital Affiliated to Heilongjiang University of Traditional Chinese Medicine between May and July 2007, were recruited into the patient group. An additional 10 healthy individuals, who received health examinations simultaneously, were included as controls.METHODS: Following admission (within 3 days) and at days 6, 12, and 30 subsequent to acute cerebral infarction attack, 3 mL venous blood was taken from each patient before the morning meal to determine the plasma level of NSE by enzyme-labeled immunosorbent assay. One-time blood extraction was performed in each healthy subject during the health examination for the same purpose as in patients. At 6 and 30 days following acute cerebral infarction attack, CT examination was performed for calculation of cerebral infarction volume according to the Tada formula. Following admission and at 30 days of disease invasion, all patients were scored by the National Institutes of Health Stroke Scale (NIHSS, 13 items).MAIN OUTCOME MEASURES: Comparison of NSE plasma level between acute cerebral infarction patients and healthy individuals; correlations of NSE plasma level in acute cerebral infarction patients with cerebral infarction volume, NIHSS score, and prognosis.RESULTS: Following admission and at days 6 and 12 of disease invasion, the plasma level of NSE was significantly higher in the patient group than in the control group (P< 0.05). Following admission and at day 30 of disease invasion, the NIHSS scores of the patient group were 17.706 and 11.222, respectively. Following admission and at day 6 of disease invasion, the plasma level of NSE was positively correlated with cerebral infarction volume (r= 0.503, 0.435, P< 0.05), but it was negatively correlated with NIHSS score (r= -0.571, 0.368, P< 0.05). The plasma level of NSE was mostly correlated with cerebral infarction volume, followed by NIHSS score, and lastly prognosis,with regression coefficients of 0.386, 0.343, and 0.340, respectively.CONCLUSION: The plasma level of NSE is higher in patients with acute cerebral infarction than in the healthy population. It can reflect infarct severity and predict early prognosis of acute cerebral infarction.