轻度认知功能障碍患者海马及嗅皮质微结构变化的扩散峰度成像研究

Microstructural changes of hippocampus and olfactory cortex on diffusion kurtosis images in mild cognitive impairment patients

目的应用扩散峰度成像(DKI)技术探讨伴脑白质高信号(WMH)的轻度认知功能障碍(MCI)患者海马区和嗅皮质区微结构的变化。方法选择2018年1月~2019年1月于我院西院神经内科病房住院的82例WMH患者,应用蒙特利尔认知评估量表(MoCA)评价患者认知功能,并将患者分为MCI组48例和无MCI组34例。患者行常规MRI形态学及DKI扫描。选择患者海马区和嗅皮质区为感兴趣区,测量DKI相关参数,包括平均扩散系数(MD)、轴向扩散张量(AD)、垂直扩散张量(RD)、各向异性分数(FA)、平均峰度(MK)、轴向峰度(AK)、径向峰度(RK)和峰度各向异性分数(KFA),比较2组各参数差异,且对多个兴趣区多次比较用Bonferroni校正P值,并行相关性分析。结果与无MCI组比较,MCI组重度WMH比例明显增高(37.5%vs 14.7%,P=0.038),logistic回归分析显示,重度WMH是MCI独立危险因素(OR=0.134,95%CI:0.283~0.614,P=0.01)。经Bonferroni校正P值后显示,左侧海马区,MCI组MD和RD显著高于无MCI组,AK和MK显著低于无MCI组(P=0.005、0.006、0.011和0.002)。左侧海马区,FA、MK、RK和KFA与MoCA评分呈正相关(r=0.374,0.370,0.392,0.242,P<0.05),而MD、RD与MoCA评分呈负相关(r=-0.227,-0.255,P<0.05)。结论DKI技术可评估伴WMH的MCI患者海马区和嗅皮质区微结构的变化,DKI参数对MCI的临床影像学评估有一定的应用价值。

Objective To study the microstructural changes of hippocampus and olfactory cortex in MCI patients with WMH by diffusion kurtosis imaging(DKI).Methods Eighty-two WMH patients admitted to our hospital from January 2018 to January 2019 were divided into MCI group(n=48)and MCI-free group(n=34).The cognitive function of the patients was assessed according to their MoCA scale score.The patients underwent conventional MRI and DKI scanning.Hippocampus and olfactory cortex were selected as the region of interests(ROI)for detecting the DKI-related parameters,including mean diffusion(MD)coefficient,axial diffusion(AD)coefficient,radical diffusion(RD)tensor,fractional anisotropy(FA),mean kurtosis(MK),axial kurtosis(AK),radical kurtosis(RK)and kurtosis fractional anisotropy(KFA).The DKI-related parameters were compared between the two groups.The P value in different ROI was adjuated by Bonferroni.Results The ratio of severe WHM was significantly higher in MCI group than in MCI-free group(37.5%vs 14.7%,P=0.038).Logistic regression analysis showed that severe WMH were an independent risk factor for MCI(OR=0.134,95%CI:0.283-0.614,P=0.01).The P value adjuated by Bonferroni showed that the MD coefficient and RD efficient were significantly higher while the MK and AK in left hippocampus were significantly lower in MCI group than in MCI-free group(P=0.005,P=0.006,P=0.002,P=0.011).The FA,MK,RK and KFA were positively related with the MoCA scale score(r=0.374,r=0.370,r=0.392,r=0.242,P<0.05)while the MD and RD in left hippocampus were negatively related with the MoCA scale score(r=-0.227,r=-0.255,P<0.05).Conclusion DKI can detect the microstructural changes of hippocampus and olfactory region in MCI patients with WMH and the DKI-related parameters play a certain role in assessing the clinical imaging of MCI patients.