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Objective: rat model of diffuse axonal injury (DAI) , to study the image characteristics of the the DAI occurrence the hindbrain the cadres -bit magnetic resonance diffusion tensor imaging (DTI) , to control pathomorphism performance , and immunohistochemical examination explore DAI rat brain cadres ADC value and FA value AQP4 expression , type DAI brain edema , pathogenesis and evolution to provide a theoretical basis for clinical treatment basis . Materials and Methods: 38 SD rats were randomly divided into five groups , each 6-8 Marmarou freefall injury model caused diffuse axonal injury . Each group h after injury , 6h , 12h , 24h , 72h underwent MRI scan , followed immediately killed for pathological examination . Control group of 10 rats , not the head weights to combat , the rest of the experimental procedure and the experimental group . Each group underwent conventional MRI examination , diffusion tensor imaging , HE staining , silver staining and AQP4 immunohistochemical staining . Compare DTI results with the results of pathological examination . Results: The pathological examination of brain stem brain edema , axonal swelling , shrinkage contraction ball . DAI after AQP4 upregulation peaked at 48h , the average high-density (IOD) value of 0.331 ± 0.007, and then decreased . ADC values ??increased first and then decreased apparent diffusion coefficient , 12h its peak . FA value continued to decline and , 72h reduced to a minimum . AQP4 expression and ADC values ??within 12h with a significant correlation ( P lt; 0.01 ) correlation ,24-72h 12-24h not have a significant correlation (P lt ; 0.01) . AQP4 expression and FA values ??with significant correlation ( P lt; 0.01 ) . Conclusion: DTI level in vivo non-invasive observation of brain edema and axonal pathological changes , DAI AQP4 expression changes over time , suggesting that the DAI brain edema changes . Rats DAI brainstem ADC value AQP4 expression correlation joint AQP4 expression and ADC values ??can provide a theoretical basis for the mechanism and evolution vasogenic brain edema and cytotoxic cerebral edema type after DAI .
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