摘要目的:通过[ 18F]-AV45正电子发射计算机断层显像(PET)观察β淀粉样蛋白(Aβ)阳性的颅内微出血(CMBs)患者的载脂蛋白E(ApoE)基因型及认知特点。 方法:回顾性研究，连续入选2015年9月至2018年5月在中日友好医院神经内科记忆障碍门诊就诊，有认知障碍主诉且简易智能状态检查量表(MMSE)≤26分，蒙特利尔认知评估量表(MoCA)≤25分，且头MRI的SWI序列上有CMBs的患者152例。通过制定排除标准，最终入组69例，年龄(68.8±9.3)岁。进行认知量表测定、ApoE基因筛查及[ 18F]-AV45 PET检查后，分为Aβ阳性组37例、Aβ阴性组32例，入选同期体检中心健康老年人21例为对照组。比较3组入选者认知量表和ApoE基因结果。 结果:90例入选者ApoEε4型基因的阳性率35.6%(32例)，Aβ阳性、阴性和对照组ApoEε4型基因阳性率分别为56.8%(21例)、18.8%(6例)、23.9%(5例)，3组比较差异有统计学意义( χ2＝12.467， P<0.01)；进一步两两比较，Aβ阳性组和对照组、Aβ阳性和阴性组间差异亦有统计学意义( χ2值分别为5.880、10.407， P<0.05、 P<0.01)。Aβ阴性组较阳性组深部微出血患者多[56.3%(18例)比8.1%(3例)， χ2＝18.784， P<0.01]，脑叶微出血少[12.5%(4例)比45.9%(17例)， χ2＝9.066， P<0.01]，混合型微出血差异无统计学意义( χ2＝1.556， P<0.05)。Aβ阳性组与对照组比较，所有认知领域差异均有统计学意义(均 P<0.05)，与阴性组患者比较记忆力、执行、视空间、和语言功能差异有统计学意义(均 P<0.05)。而Aβ阴性组与对照组执行功能、视空间及注意力比较，差异有统计学意义(均 P<0.05)。 结论:有Aβ沉积的CMBs患者其认知障碍损伤更广泛、更严重，且与ApoEε4等位基因的阳性有关。

abstractsObjective:To analyze the characteristics of the apolipoprotein E(Apo E)genotype and cognitive impairment in patients with cerebral microbleeds(CMBs)and positive β-amyloid(Aβ)by using [18F]-AV45 positron emission tomography(PET).Methods:From September 2015 to May 2018, 152 patients with cognitive impairment and CMBs on the susceptibility-weighted imaging(SWI)sequence of head MRI at the neurology department of our hospital, assessed by mini-mental status examination(MMSE)score ≤26 and Montreal cognitive assessment(MoCA)≤25, were consecutively recruited in this retrospective study.After assessment with the inclusion and exclusion criteria, 69 patients aged 68.8±9.3 years were considered eligible for further analysis.Patients were divided into the Aβ-positive group(Aβ + Group, n=37)and the Aβ-negative group(Aβ -Group, n=32)after cognitive assessment, ApoE genotyping and [18F]-AV45 PET examination.Twenty-one healthy elderly controls(HC Group)who took health examination during the same period were enrolled.The results of cognitive assessment and Apo E genotyping were compared between the three groups. Results:The positive rate of the ApoE ε4 allele was 35.6%(32/90), 56.8%(21/37), 18.8%(6/32), and 23.9%(5/21)in the Aβ + , Aβ -and HC groups, respectively, with statistical significant differences between the groups( χ2=12.467, P<0.01). There were significant differences in the positive rate of the ApoE ε4 allele between the Aβ + and HC groups and between the Aβ + and Aβ -groups( χ2=5.880 and 10.407, P<0.05 and P<0.01). The percentage of patients with deep cerebral microbleeds was higher(56.3% or 18/32 vs.8.1% or 3/37, χ2=18.784, P<0.01)and of patients with lobar hemorrhage was lower(12.5% or 4/32 vs.45.9% or 17/37, χ2=9.066, P<0.01)in the Aβ -group than in the Aβ + group, while there was no significant difference in the percentage of patients with mixed cerebral microbleeds between the Aβ -and Aβ + groups( χ2=1.556, P>0.05). There were significant differences in cognitive function between the Aβ + and HC groups, in memory, executive function, visuospatial ability and language between the Aβ + and Aβ -groups, and in executive function, visuospatial ability and attention between the Aβ -and HC groups. Conclusions:Cognitive impairment is more extensive and severe in CMBs patients with Aβ deposition and is associated with positive ApoE ε4.