弥散张量成像对遗忘型轻度认知障碍诊断和预后评估的价值

Value of Diffusion Tensor Imaging in the Diagnosis and Prognosis of Amnestic Mild Cognitive Impairment

目的探讨磁共振弥散张量成像(DTI)评估遗忘型轻度认知障碍(aMCI)患者的诊断和预后价值。方法选取2012年7月—2015年4月河北省唐山市工人医院临床诊断为aMCI的患者115例,根据损害认知领域的情况分为单一遗忘型轻度认知损害(aMCI-s)组(60例)和多领域遗忘型轻度认知损害(aMCI-m)组(55例)。分别在就诊时、出院后第12个月时对患者进行神经心理学测试、影像学DTI扫描,评估患者转归情况以及感兴趣区各向异性分数(FA)值、表观扩散系数(ADC)值。结果随访结束后,由于患者死亡、颅脑影像学异常、无故失访等情况,最终共纳入94例患者,其中aMCI-s组50例,aMCI-m组44例。94例患者中有24例12个月后转化为阿尔茨海默病(AD),总转化率为25.5%。aMCI-s组和aMCI-m组AD转化率分别为16.0%(8/50)和36.4%(16/44),两组AD转化率比较,差异有统计学意义(χ2=5.10,P=0.02)。aMCI-s组胼胝体膝部、胼胝体压部、扣带回FA值高于aMCI-m组,胼胝体膝部、额枕下束、上纵束ⅡADC值低于aMCI-m组,差异均有统计学意义(P<0.05)。aMCI-s组胼胝体膝部、胼胝体压部、扣带回FA值高于aMCI-s转化为AD组,胼胝体膝部、胼胝体压部、扣带回、上纵束ⅡADC值低于aMCI-s转化为AD组,差异均有统计学意义(P<0.05)。aMCI-m组胼胝体膝部、扣带回、额枕下束FA值高于aMCI-m转化为AD组,胼胝体膝部、扣带回、上纵束ⅡADC值低于aMCI-m转化为AD组,差异均有统计学意义(P<0.05)。aMCI-s转化为AD组和aMCI-m转化为AD组胼胝体膝部、胼胝体压部、扣带回、额枕下束、上纵束ⅡFA值比较,差异均无统计学意义(P>0.05);aMCI-s转化为AD组胼胝体膝部、胼胝体压部、扣带回、额枕下束、上纵束ⅡADC值低于aMCI-m转化为AD组,差异均有统计学意义(P<0.05)。结论 aMCI-m较aMCI-s更容易发展为AD,DTI能够反映aMCI的病理变化程度,鉴别诊断aMCI类型并判断其预后。

Objective To investigate the value of diffusion tensor imaging（DTI）in the diagnosis and prognosis of amnestic mild cognitive impairment（ aMCI）. Methods From July 2012 to April 2015,we enrolled 115 patients who were diagnosed with aMCI in Tangshan Gongren Hospital in Hebei Province. According to the domains of cognitive damage,the patients were divided into two groups：single - domain aMCI group（ aMCI-s group,n = 60 ） and multiple - domain aMCI group （aMCI-m group,n = 55）. When receiving the first treatment and 12 months after discharge from hospital,neuropsychological test and imaging DTI scan were conducted on the patients,and relapse,FA values and ADC values of regions of interest were evaluated. Results When follow - up ended,94 patients were at last included after the exclusion of patients who died,had brain imaging abnormality and got lost for no reason. Among the 94 patients,50 patients were assigned into aMCI-s group,and 44 patients were assigned into aMCI-m group. Among them,24 patients had disease translating into alzheimer＇s disease 12 months after discharge,and the overall translation rate was 25. 5% . The translation rates of the aMCI-s group and the aMCI-m group were 16. 0% （8 / 50）and 36. 4% （16 / 44）,and the two groups were significantly different in AD translation rate（χ^2 = 5. 10, P = 0. 02）. The aMCI-s group was higher than the aMCI-m group in FA values of corpus callosum knee,splenium of corpus callosum,cingulate fasciculus,and the aMCI-s group was lower than aMCI-m group in ADC value of corpus callosum knee, inferior fronto - occipital fasciculus and superior longitudinal fasciculus Ⅱ（P 〈 0. 05）. The aMCI-s group was higher than the aMCI-s-AD group in the FA values of corpus callosum knee,splenium of corpus callosum and cingulate fasciculus,and the aMCI-s group was lower than the aMCI-s-AD group in the ADC values of corpus callosum knee,splenium of corpus callosum, cingulate fasciculus and superior longitudinal fasciculus Ⅱ（P 〈 0. 05）. The aMCI-m group was higher than the aMCI-m-AD group in corpus callosum knee,cingulate fasciculus and inferior fronto - occipital fasciculus,and the aMCI-m group was lower than the aMCI-m-AD group in ADC value of corpus callosum knee,cingulate fasciculus and superior longitudinal fasciculus Ⅱ（P 〈 0. 05）. The aMCI-s-AD group and the aMCI-m-AD group were not significantly different in the FA values of corpus callosum knee,splenium of corpus callosum,cingulate fasciculus,inferior fronto - occipital fasciculus and superior longitudinal fasciculus Ⅱ（P 〉 0. 05）;the aMCI-s-AD group was lower than the aMCI-m-AD group in ADC values of corpus callosum knee, splenium of corpus callosum,cingulate fasciculus,inferior fronto - occipital fasciculus and superior longitudinal fasciculus Ⅱ（P 〈 0. 05）. Conclusion aMCI-m is more likely to develop into AD than aMCI-s,and DTI could reflect the pathological changes of aMCI and could be used to determine aMCI types and predict its prognosis.