Abstract:

Objective To study the characteristics of cerebral hemodynamics and the correlation with cognitive function in patients with mild cognitive impairment (MCI). Methods A total of 80 cases were divided into MCI group (N = 40) and control group (N = 40). Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to evaluate the cognitive function of 2 groups. Bilateral middle cerebral artery (MCA) and basilar artery (BA) were examined by means of transcranial Doppler (TCD) ultrasound to obtain mean flow velocity (MFV), pulsatility index (PI), resistance index (RI) and the ratio of peak systolic velocity to end-diastolic velocity (S/D) in all subjects. Results Compared with control group, PI (P = 0.023) and RI (P = 0.035) of MCA were significantly increased in MCI group. The differences in MFV, S/D and hemodynamic indexes of BA had no significance between 2 groups (P > 0.05, for all). The rate of abnormal PI of MCA in MCI group was higher than that in control group [45% (18/40) vs. 20% (8/40); χ² = 4.615, P = 0.032]. Pearson correlation analysis showed that PI of MCA had negative correlation with MoCA score in MCI group (r = -0.382, P = 0.036), and no correlation with MMSE score (P > 0.05). MFV, RI and S/D of MCA and MFV, PI, RI and S/D of BA had no correlation with MoCA and MMSE scores (P > 0.05, for all). MCI group was further divided into subgroups according to PI, and MoCA score was significantly lower in abnormal PI subgroup than that in normal PI subgroup [(18.57 ± 3.02) score vs. (23.41 ± 2.78) score; t = 3.914, P = 0.015]. Conclusions Cerebral hemodynamics in MCI patients was changed. The cognitive impairment was closely related to the increase of PI in MCA.

Key words: Cognition disorders, Hemodynamics, Middle cerebral artery, Basilar artery, Ultrasonography, Doppler, transcranial

摘要：

目的 探讨轻度认知损害（MCI）患者脑血流动力学特点及其与认知功能的相关性。方法 采用简易智能状态检查量表（MMSE）和蒙特利尔认知评价量表（MoCA）评价40 例轻度认知损害患者及性别和年龄相匹配的40 例正常对照者的认知功能，经颅多普勒超声检测双侧大脑中动脉和基底动脉平均血流速度、搏动指数、阻力指数、收缩期峰值流速与舒张末期流速比值。结果 MCI 组患者大脑中动脉搏动指数（P = 0.023）和阻力指数（P = 0.035）高于对照组，而平均血流速度和收缩期峰值流速与舒张末期流速比值以及基底动脉各项血流动力学指标差异均无统计学意义（P > 0.05）。MCI组患者大脑中动脉搏动指数异常率高于对照组［45%（18/40）对20%（8/40）；χ² = 4.615，P = 0.032］。Pearson 相关分析显示，MCI 组大脑中动脉搏动指数与MoCA 评分呈负相关（r = -0.382，P = 0.036），与MMSE 评分无关联性（P > 0.05）；而平均血流速度、阻力指数和收缩期峰值流速与舒张末期流速比值以及基底动脉各项血流动力学指标与MMSE 和MoCA 评分均无关联性（P > 0.05）。根据搏动指数将轻度认知损害患者进一步分组，搏动指数异常亚组MoCA 评分低于搏动指数正常亚组［（18.57 ± 3.02）分对（23.41 ± 2.78）分；t = 3.914，P = 0.015］。结论 轻度认知损害患者存在脑血流动力学改变，尤以大脑中动脉搏动指数升高与认知功能障碍的关系最为密切。

关键词: 认知障碍, 血流动力学, 大脑中动脉, 基底动脉, 超声检查, 多普勒, 经颅