【摘要】 目的探讨磁共振扩散张量成像(DTI)技术及评价指标在各期脑梗死的变化规律及临床应用价值。资料与方法对75例脑梗死患者进行91例次DTI检查,其中超急性期11例次,急性期15例次,亚急性期38例次,稳定期10例次,慢性期17例次。观察各期脑梗死灶在平均扩散系数(DCavg)图、部分各向异性(FA)图、容积比各向异性(VRA)图上的表现,分别测量最大层面梗死灶灰质与受累白质束及对侧相应部位的DCavg值、FA值、VRA值,并计算相对r值进行统计学分析。结果超急性期、急性期、亚急性期脑梗死灶灰白质区DCavg较对侧明显下降(P<0.001),在超急性期、急性期最低,以后随时间延长逐渐上升,于8～14天出现假正常化(P>0.05),在慢性期较对侧明显升高(P<0.001);经分析rDCavg与时间具有显著相关性(r=0.992,P<0.001)。梗死区灰白质的DCavg值差异无统计学意义(t=-0.39,P>0.05),灰白质内各梗死期之间差异有统计学意义(F灰质=72.18,F白质=64.0;P<0.001)。超急性期脑梗死白质区FA较对侧上升(t=3.83,P=0.003),急性期与对侧差异无统计学意义(t=0.44,P>0.05),以后明显下降(P<0.001)。灰质的FA及VRA与对侧比较改变不明显(P>0.05),各梗死期之间差异无统计学意义(FFA=0.17,P=0.14;FVRA=2.0,P=0.10)。rVRA的改变与rFA相似,两者之间有显著性相关(r白质=0.888,r灰质=0.74,P<0.001);其他组之间无明显相关性(P>0.05)。rFA、rDCavg及rVRA组间有明显差异(F=72.73,P<0.001)。结论不同时期脑梗死灶的DTI参数值演变规律具有特征性,可以利用DTI对脑梗死进行分期诊断。更多还原

【Abstract】 Objective To study the change regularity of several evaluating indexes of diffusion tenor imaging(DTI) in monitoring the development of cerebral infarction and defining the infarction stages.Materials and Methods91 work-ups in 75 patients with cerebral infarction(11 hyperacute,15 acute,38 subacute,10 steady,and 17 chronic) were performed with conventional MRI,DWI and DTI,and then the parametric maps were reconstructed.The values of DCavg,FA,VRA in the center infarct lesion involved gray matter and white matter as well as those of contralateral infarct areas were measured.The data from the average values and relative values of those were analyzed statistically,including paired T test,correlation analysis,and analysis of variance.ResultsThe average DCavg values of hyperacute,acute and subacute infarcts were significantly decreased compared with that of homologous contralateral tissue respectively(P<0.001).The average DCavg values in hyperacute and acute stage were minimized,and increased progressively as time passed and appeared as"pseudonormal" values in approximately 8 to 14 days.Thereafter,DCavg values became greater than normal in chronic stage(P<0.001).There was positive correlation between rDCavg values and time(r=0.992,P<0.001).The average DCavg values between the white matter and the gray matter in infarct area were not significant(t=-0.39,P>0.05),and were significant in the infarction stages(P<0.001).The average FA value of the white matter in hyperacute infarcts was increased compared with that of homologous contralateral tissue(P<0.05),and that of acute infarct was not significant(P>0.05),and significantly decreased as time passed(P<0.001).The average FA and VRA values of the gray matter between infarct area and homologous contralateral tissue were not significant(P>0.05),in the infarction stages were also not significant(P>0.05).There was good correlation between rFA values and rVRA values(P<0.001),and no correlation with others,respectively(P>0.05).The changing magnitude of rFA,rDCavg and rVRA values in lesions compared with others indexes were significant(P<0.001),respectively.ConclusionThere is characteristic feature in changes of FA,DCavg and VRA values.DTI can differentiate different stages of cerebral infarction.更多还原