ApoEε4等位基因对认知正常老年人脑微观结构影响的扩散峰度成像研究

Diffusion kurtosis imaging study: the effects of ApoE epsilon4 alleles on brain microstructure in healthy elders

目的通过应用磁共振扩散峰度成像(diffusion kurtosis imaging,DKI)技术评估认知正常的老年人中携带和非携带载脂蛋白Eε4(apolipoprotein Eε4,ApoEε4)等位基因者脑微观结构的差异,进而探讨ApoEε4等位基因对脑微观结构的影响。方法收集18例正常老年人口腔黏膜,检测是否携带ApoEε4基因;同时对其行常规核磁共振成像(magnetic resonance imaging,MRI)平扫及DKI扫描,分别于双侧额、顶、颞叶,后扣带回、胼胝体压部及海马测量平均峰度(mean kurtosis,MK)值及各项异性分数(fractional anisotraphy,FA)值,采用两样本t检验对携带与非携带ApoEε4基因所得的参数进行比较。结果认知正常老年人携带ApoEε4等位基因组与非携带组比较,颞叶及海马MK值减低,且差异有统计学意义(P<0.05);海马的FA值减低,差异有统计学意义(P<0.05)。结论认知正常老年人携带ApoEε4等位基因的受试者脑微观结构改变更加明显,DKI能够早期发现该等位基因对于脑微观结构改变的影响。

Objective To compare the difference of the brain microstructure between apolipoprotein Eε4 （ApoEε4） allele carriers and noncarriers of normal elderly people with normal cognitive state and to explore the influence of ApoEε4 alleles on its brain microstructure by using diffusion kurtosis imaging （DKI） magnetic resonance technology.Methods The ApoEε4 alleles was detected in oral mucosa of 18 normal elders;All subjects underwent routine magnetic resonance imaging（MRI） scanning and DKI scanning.Mean kurtosis（MK） and fractional anisotraphy（FA） values were measured in bilateral frontal lobe,parietal lobe,temporal lobe,posterior cingulate cortex,splenium of corpus callosum and hippocampe.The two-sample t-test was used to compare the parameters between the ApoEε4 allele carriers and noncarriers.Results MK value in the temporal lobe and hippocampus of the ApoEε4 allele carriers was significantly lower than in that of noncarriers （P〈0.05）.FA value in the hippocampus of the ApoEε4 allele carriers was significantly lower than in that of noncarriers （P〈0.05）.Conclusion Microstructural changes of the brain of ApoEε4 alleles carriers in normal elderly persons with normal cognitive state are more obvious.DKI could detect the influence of ApoEε4 allele on the microstructural changes of the brain in the eraly time.