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目的 用弥散磁共振成像观察实验性脑梗死灶水表面弥散系数 (apparentdiffusioncoefficient,ADC)值的变化。方法 用 60只SD大鼠行易卒中型肾血管性高血压 (RHRSP)模型 ,在术后 1 0周按Longa’s方法改良行左侧大脑中动脉闭塞 (MCAO)术。分别在闭塞 1 2h内的不同时间点及再灌注 48h后行T2加权成像 (T2WI)、磁共振弥散加权成像 (DWI) ,完成检查后将大鼠处死行TTC染色 ,比较在闭塞不同的时间点上在两次T2WI和DWI上病灶的演变和ADC值的改变。结果 缺血中心区的ADC值为 ( 0 45± 0 0 1 )× 1 0 - 5cm2 /s,半暗带为 ( 0 5 6± 0 0 2 )× 1 0 - 5cm2 /s,对侧平均值为 ( 0 66± 0 0 2 )× 1 0 - 5cm2 /s,相邻正常信号组织平均值为 ( 0 65± 0 0 3)× 1 0 - 5cm2 /s,经方差分析表明 ,前三者相互之间比较均有显著性差异 (P <0 0 0 1 ) ,而后两者之间比较无显著性差异 (P >0 0 5 ) ;再灌注 48h后 ,在 3h内复流各组梗死灶的平均ADC值为 ( 0 65± 0 0 2 )× 1 0 - 5cm2 /s ,与相邻正常信号组织相比无显著性差异 (P>0 0 5 )。而在 6h后复流各组的平均ADC值为 ( 0 70± 0 0 3)× 1 0 - 5cm2 /s,与相邻正常信号组织相比有显著性差异(P <0 0 5 )。结论 实验性MCAO 1 2h内缺血或梗死灶的ADC值降低 ,而再
Objective To observe the change of apparent diffusion coefficient (ADC) of experimental cerebral infarction by diffusion magnetic resonance imaging. Methods Sixty SD rats were subjected to stroke-induced renovascular hypertension (RHRSP). Long-term middle cerebral artery occlusion (MCAO) was performed by Longa’s method at 10 weeks after operation. T2 weighted imaging (T2WI) and diffusion weighted imaging (DWI) were performed at different time points within 12 hours of occlusion and 48 hours after reperfusion. TTC staining was performed after the rats were sacrificed at the completion of the examination. At different time points of occlusion Changes in lesion and ADC values on two T2WI and DWI. Results The ADC value of the ischemic center was (0 45 ± 0 0 1) × 10 5 cm 2 / s and the penumbra was (0 5 6 ± 0 0 2) × 10 5 cm 2 / s. The contralateral average (0 66 ± 0 0 2) × 1 0 - 5 cm 2 / s, and the average value of adjacent normal signal tissues was (0 65 ± 0 0 3) × 10 5 cm 2 / s. The variance analysis showed that the former three (P <0.01), but there was no significant difference between the two groups (P> 0.05). After reperfusion for 48h, the infarction size The average ADC value was (0 65 ± 0 0 2) × 10 5 - 5 cm 2 / s, which was not significantly different from the adjacent normal tissue (P 0 05). However, the mean ADC value of all groups after reperfusion at 6h was (0 70 ± 0 0 3) × 10 5 cm 2 / s, which was significantly different from that of adjacent normal tissues (P 0 05). Conclusions The ADC value of ischemic or infarcted lesion in experimental MCAO reduced within 1 h, and then again