颈动脉狭窄或闭塞患者数字记忆的功能磁共振成像研究

目的:探讨左侧颈内动脉/大脑中动脉狭窄和闭塞患者与正常人数字工作记忆的激活脑区差异及其记忆障碍的脑加工机制。方法:对12例左侧颈动脉狭窄/闭塞患者(其中左侧颈内动脉狭窄4例,左侧颈内动脉闭塞2例,左侧大脑中动脉狭窄5例,左侧大脑中动脉闭塞1例,24例正常对照组进行数字记忆任务的功能磁共振成像,采用AFNI软件进行数据分析和脑功能区活动图像。结果:左侧颈内动脉/大脑中动脉狭窄和闭塞患者的反应时间较对照组显著延长(P0.05),正确率较对照组明显降低(P0.05)。脑激活图显示数字工作记忆的编码期、保持期、提取期患者组的脑激活明显少于正常对照组,而且脑激活的左侧半球优势减弱,右侧半球出现代偿性激活,其中提取期最为明显。结论:左侧颈动脉狭窄/闭塞患者数字记忆任务的脑激活区存在损害,功能磁共振成像研究能为早期诊断认知障碍提供影像学依据。

Functional MRI study of digital working memory in patients with carotid artery stenosis or occlusion

Objective：To explore the difference of digital working memory between the healthy subjects and the patients with left internal carotid artery（ICA） / middle cerebral artery（MCA） stenosis or occlusion using functional magnetic resonance imaging（fMRI）.Methods：fMRI were acquired in 12 patients with left ICA/ MCA stenosis or occlusion（4 cases with ICA stenosis,2 case with ICA occlusion,5 cases with MCA stenosis,1 with MCA occlusion） and 24 healthy subjects when they received digital working memory experiment.AFNI was used to process fMRI data and localize functional areas of brain.Results：The patient group showed longer reaction time and lower correct ratio（P0.05） compared with the control group.Compared with the normal control group,the patients demonstrated fewer activated brain regions during three phase（encode,maintain and retrieve phase） of digital task.The decreased left hemisphere dominant activations and increased right hemisphere compensatory activations were found.It was the most prominent during retrieval phase in patients.Conclusion：This study reveals the deficits of digital working memory in patients with left ICA/MCA stenosis or occlusion.These findings will play important roles for the early diagnosis of cognitive impairment.