阿尔茨海默病脑灰质核团微观结构的弥散峰度成像研究

Diffusion Kurtosis Imaging Study of Gray Nucleus Microstructure in Alzheimer's Disease

目的应用弥散峰度成像(DKI)研究阿尔茨海默病(AD)患者脑灰质核团微观结构变化的状况。方法搜集23例AD患者和24例健康对照者,行常规MRI序列及DKI扫描,手动测量尾状核头、壳核、苍白球、丘脑、红核、黑质、齿状核的DKI参数:弥散峰度(MK)、轴向峰度(Ka)、径向峰度(Kr)、平均弥散率(MD)、轴向弥散率(Da)、径向弥散率(Dr)及各向异性分数(FA)值。DKI参数诊断AD的能力采用ROC曲线分析,DKI各参数与MMSE评分之间的相关性采用Pearson相关分析。结果 AD组与健康对照组(HC组)相比,尾状核头的MK值、黑质的MK、Ka及Kr值升高(P<0.05),丘脑的MK、Ka及Kr值、齿状核的Ka值减低(P<0.05);丘脑、尾状核头、壳核、红核、齿状核的MD值升高(P<0.05),丘脑、尾状核头、壳核、苍白球、齿状核的Da值升高(P<0.05),尾状核头、苍白球及齿状核的Dr值升高(P<0.05);苍白球、黑质的FA值减低(P<0.05),尾状核头、红核、齿状核的FA值升高(P<0.05)。苍白球Dr值的ROC曲线下面积(AUC=0.810)最大。各部位的MD、Da及Dr值、黑质的Ka值以及尾状核头的FA值与MMSE评分均呈负相关(P<0.05);丘脑的MK、Ka值以及红核、黑质的FA值与MMSE评分呈正相关(P<0.05)。结论 AD患者灰质核团的微结构存在病理性变化,利用DKI可以定量评估灰质核团微结构变化的状况,灰质核团中苍白球的Dr值是鉴别AD与HC的最佳指标。

Objective To initially study the state of gray nucleus microstructure change of Alzheimer＇s disease（ AD）with diffusion kurtosis imaging（ DKI）. Methods Twenty three cases of AD and twenty four cases of volunteers were examined with conventional MRI scan and DKI sequence. Bilateral MK values,Ka values,Kr values,MD values,Da values,Dr values and FA values of the head of caudate nucleus,putamen,globus pallidus,thalamus,red nucleus,substantia nigra and dentate nucleus were measured. ROC curves were used to assess the ability of regional diffusion measures to diagnose AD. The correlations between DKI parameters and MMSE score were tested using Pearson＇s correlation. Results Compared to the HC group,the mean value of MK in the head of caudate nucleus and the mean value of MK,Ka,Kr of the substantia nigra in the AD group significantly increased. The mean value of MK,Ka,Kr in the thalamus and the mean value of Ka in the dentate nucleus in the AD group significantly decreased. MD value in the thalamus,head of caudate nucleus,putamen,red nucleus and dentate nucleus significantly increased. Da value increased in the thalamus,head of caudate nucleus,putamen,globus pallidus and dentate nucleus. Dr value increased in the head of caudate nucleus,globus pallidus and dentate nucleus. FA value decreased in the globus pallidus and substantia nigra and increased in the head of caudate nucleus,red nucleus and dentate nucleus. The biggest area under ROC curve（ AUC） value of 0. 810 belonged to the Dr value in the gray nucleus. In all regions,the negative correlation was present between MD value,Da value,Dr value and MMSE score. Ka value and MMSE in the substantia nigra showed the negative correlation. MK,Ka value and MMSE in the thalamus showed the positive correlation. FA value and MMSE score in the head of caudate nucleus showed the negative correlation. FA value and MMSE score in the red nucleus and substantia nigra showed the positive correlation. Conclusion Microstructure of gray nucleus exhibiting pathological changes in patients with AD and DKI can be used to quantitatively evaluate the status of the gray nucleus microstructure. The Dr value in the globus pallidus of gray nucleus can be the best individual biomarker of differentiation of AD to controls.