Correlation of DTI and AQP-4 in newborn piglets with early stage hypoxic-ischemic injury

Objective To assess the value of DTI in the early stage of brain with hypoxic-ischemic (HI) injury and the correlation between DTI and AQP-4. Methods Thirty hypoxic-ischemic injury models in newborn piglets were performed and evenly divided into six groups by time points (2, 6, 12, 24, 48, 72 h) after HI injury, while 5 newborn piglets underwent sham operation as control group. At each time point, DTI and AQP-4 expression were observed and compared. Results In neostriatum, cytotoxic edema continued for 72 h and reached minimum at 24 h with decrease of ADC values at different time points (F=27.42, P0.05), and significant positive correlation was found between ADC value and optical density (OD) value of AQP-4 (r=0.875, P0.05). In the border region, cytotoxic edema began to appear at 6 h after HI injury and then vasogenic edema appeared and became predominant gradually. ADC value increased after a transient decrease and reached the peak at 48 h (F=50.25, P0.05). The change of ADC value was concordant with the OD value of AQP-4, but no statistical correlation was found (r=0.505, P0.05). The FA value decreased after HI. Conclusion DTI can be used to detect the brain edema in the early stage of HI injury. The change of ADC value correlates with that of AQP-4 expression.