| Partâ… A dynamic evolution of MR diffusion imaging in vasogenicbrain edema model of Wistar ratsObjective: To establish the best scan mode and the dynamic evolution mode ofdiffusion imaging in vasogenic brain edema(VBE) model of Wistar rats through theanalysis of the correlations between the parameters of diffusion imaging and watercontent of brain tissue. To evaluate the value of diffusion imaging in quantification ofbrain water content in vivo. To establish the dynamic evolution mode of S-100B inserum. Materials and Methods: VBE model of Wistar rats was made by cold injurywith copper rod which cooled with liquid nitrogen. There were 11 groups(normalcontrol, 2hrs, 4hrs, 6hrs, 8hrs, 12hrs, 24hrs, 48hrs, 3d, 5d and 7d), and each group had6 rats. Diffusion weighted imaging(DWI) with 3 b values (1000s/mm2, 1400s/mm2,1800s/mm2), diffusion tensor imaging(DTI) with b=1000s/mm2 and fast spinecho-iversion recovery(FSE-IR) T1 weighted image were performed, the values ofapparent diffusion coefficient(ADC), exponential apparent diffusion coefficient(eADC), average diffusion coefficient(DCavg), fractional anisotropy(FA) and T1 werecalculated in the lesion side and contralateral side, the corresponding brain tissueswere gotten to calculate the water content. Blood samplings from venae femoraliswere used to test the level of S-100B in serum. ANONA were used to analysis thedifferences of the signal noise ratio(SNR) of DWI, the parameters of different bvalues and the dynamic evolutions of the parameters of diffusion imaging in the sameb value, T1 time, water content of brain tissues and the level of S-100B in serum. Thecorrelations between the parameters of diffusion imaging, the level of S-100B inserum and the water content of brain tissue were analyzed with pearson correlationanalyzation. Results:â‘ The SNR was best when b=1000s/mm2, and SNR showeddifferent changing mode in different b values, and when b=1000s/mm2 the lesionswere more obvious because of T2 shine through effect;â‘¡ADC values were decreased when b values were increased, and eADC values were opposite;â‘¢The water contentof brain tissues first increased and then decreased with the time evolution, and therewas no significant difference in groups between 4hrs, 6hrs and 8hrs;â‘£The values ofADC, eADC, DCavg, FA and T1 showed good correlations with the water content ofbrain tissue, and the ADC values of b=1000s/mm2 had the highest correlationcoefficient;⑤The level of S-100B in serum had the peak value in 24hrs group, andhad a low correlation coefficient with the water content of brain tissue. Conclusion:â‘ 2 minutes is the most suitable time for cold injury in this model, and removing thesoft tissues of scalp and keeping the local site dry are the key points to avoid theartifact of the diffusion imagings, 8 groups(2hrs, 6hrs, 12hrs, 24hrs, 48hrs, 3d, 5d and7d) are made sure to observe the VBE evolution;â‘¡b=1000s/mm2 is the best b value,ADC shows the best correlation with the water content of brain tissue whenb=1000s/mm2, and it can be used to quantitative analysis the water content of braintissue in vivo. DTI has a longer scan time compared with DWI and the parameters ofDTI have no advantage of correlations with the water content of brain tissues. We canchoose the DWI for in vivo quantification of the water content of brain tissues whenthe anisotropy of tissue is not the focal point to observe in order to save the scantime;â‘¢The T1 values show the good correlation with the water content of braintissue, but it's scan time is much longer than DWI, so ADC values of DWI are moresuitable to measure the water content of brain tissue in vivo;â‘£The dynamicevolution mode of S-100B in serum can be the evaluating indicator of the degree ofcerebral tissue injury.Partâ…¡A dynamic analysis of permeability of blood brain barrier invasogenic brain edema model of Wistar ratsObjective: To analysis the dynamic evolution mode of permeability of bloodbrain barrier in VBE model of Wistar rats through the quantification of Evans blue ofbrain tisse, and to make sure whether the Evans blue has influence on measurement ofparameters of diffusion imaging. Materials and Methods: VBE model of Wistar rats was made by cold injury with copper rod which cooled with liquid nitrogen. Therewere 11 groups(normal control, 2hrs, 4hrs, 6hrs, 8hrs, 12hrs, 24hrs, 48hrs, 3d, 5d and7d), and each group had 6 rats. Evans blue was injected through venae femoralis 2hrsbefore the time points, DWI and DTI with b=1000s/mm2 were performed, the valuesof ADC, eADC, DCavg and FA were calculated in the lesion side and contralateralside, the corresponding brain tissues were gotten to calculate the water content andthe content of Evans blue. Independent-samples t test was used to analysis therepeatability of the VBE model and to make sure whether the Evans blue hasinfluence on measurement of parameters of diffusion imaging. ANOVA was used toanalysis the dynamic changes of the Evans blue content of brain tissue, water contentof brain tissue, and the parameters of diffusion imaging. The correlations betweenthe parameters of diffusion imaging and the water content of brain tissue wereanalyzed with pearson correlation analyzation. Results:â‘ VBE model showed goodrepeatability throught the analysis of water content of brain tissues, and Evans bluecould make the values of ADC and DCavg decreased, and the values of eADCincreased. Evans blue had no influence on FA measurement. The correlationcoefficients were lower than the groups which had no injection of Evans blue;â‘¡The content of Evans blue of brain tissue got the peak value at 2hrs group, and itdeclined gradually, when 7d group it was still higher than normal level. Conclusion :â‘ The dynamic evolution mode of permeability of blood brain barrier is differentfrom water content of brain tissue, it gets the peak value at 2hrs group, and it declinesgradually, when 7d group it is still higher than normal level;â‘¡Evans blue hasinfluence on parameters of average diffusion ability, and has no influence onparameters of diffusion anisotropy. The leakage of Evans blue in the lesion site couldhave influence on the molecular binding situation of water, the parameters ofdiffusion imaging after Evans blue injections also show the good correlation with thewater content of brain tissues.Partâ…¢A dynamic evolution of AQP-4 immunohistochemistry staining in vasogenic brain edema model of Wistar ratsObjective: To analysis the dynamic evolution mode of aquaporin-4 expression ofependymal cells in VBE model of Wistar rats through the semi-quantification ofimmunohistochemistry staining, and analysis of the correlations between theparameters of diffusion imaging and AQP-4 expression. Materials and Methods:VBE model of Wistar rats was made by cold injury with copper rod which cooledwith liquid nitrogen. There were 11 groups(normal control, 2hrs, 4hrs, 6hrs, 8hrs,12hrs, 24hrs, 48hrs, 3d, 5d and 7d), and each group had 6 rats. DWI and DTI withb=1000s/mm2 were performed, the values of ADC, eADC, DCavg and FA werecalculated in the lesion side and contralateral side, the corresponding slice of the braintissues were gotten to stain with immunohistochemical technique. Thesemi-quantification of immunohistochemistry staining of AQP-4 was made bysoftware imagepro-plus through the value of integrate optical density(IOD). ANOVAwas used to analysis the dynamic changes of the AQP-4 expression. The correlationsbetween the parameters of diffusion imaging and AQP-4 expression were analyzedwith pearson correlation analyzation. Results:â‘ The expression of AQP-4 showed atrend of first down-regulate, then up-regulate and last down-regulate. 2hrs group hadobvious down-regulation and 6hrs group had the lowest value, and 8hrs groupshowed up-regulation, 24hrs group got the peak value, then the expression of AQP-4gradually down-regulated, 7d group it was still higher than normal;â‘¡The correlationcoefficients between expression of AQP-4 and the parameters of diffusion imagingwere low, they were 0.2902～0.4475. Conclusion: The dynamic evolution of AQP-4of the ependymal cells is first down-regulated, then up-regulated and lastdown-regulated, this trend make the fund for further pharmacology study.
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