成人大脑皮质老化形态学改变的MRI研究

目的 探讨成人大脑正常衰老过程中大脑皮质体积、厚度及表面积改变的区域性差异及侧化差异MRI的表现。方法 采用前瞻性研究。2017年9月—2018年1月山东省立医院影像科及寿光市人民医院CT磁共振室招募18~85岁右利手汉族健康成年志愿者109人,其中男性56人、女性53人,年龄(53.13±15.61)岁,均行3.0 T MRI颅脑扫描原始数据。使用FreeSurfer脑成像软件分析,获取左右大脑半球、各脑叶的感兴趣区脑皮质的体积、厚度及表面积的具体数值并进行标准化处理,分析其与年龄的相关关系,以及大脑皮质老化的区域性差异及侧化差异。结果 线性回归分析显示,大脑皮质体积、厚度及表面积随年龄增长而下降(P＜0.01),表现出与年龄相关的皮质体积减少较多的区域为海马旁回、额下回岛盖部、额中回、额下回三角部、舌回、颞中回(最大为-0.653%/岁,P＜0.01),皮质厚度减少较多的区域主要在颞上回、后扣带回、额中回、外眶额回、顶下缘角回、颞极、海马旁回(最大-0.009 mm/岁,P<0.01),皮质表面积减少较多的区域主要是在海马旁回、舌回、颞下回、额中回、额下回岛盖部(最大-0.402%/岁,P＜ 0.01)。大脑左右半球皮质体积年龄效应不对称的区域为额上回、额下回岛盖部及三角部、中眶额回、额极、顶下缘角回、缘上回、梭状回、颞极、海马旁回、前扣带回、内嗅皮层(P＜0.05),皮质厚度年龄效应不对称的区域为额上回、额下回岛盖部、中眶额回、楔叶、颞下回、颞极、前扣带回、后扣带回(P＜0.05),皮质表面积年龄效应不对称的区域为额上回、额中回、额下回岛盖部及三角部、中眶额回、额极、顶下缘角回、缘上回、梭状回、颞极、海马旁回、前扣带回、后扣带回、内嗅皮层(P＜0.05)。结论 在人脑的正常老化过程中,大脑皮质体积、厚度及表面积与年龄呈现线性负相关性改变,不同脑区皮质与年龄呈不同程度的线性负相关关系,部分脑回皮质的年龄效应存在侧化差异,皮质体积、厚度、表面积三个形态学指标是相互关联的。

MRI study on morphological changes of adult cerebral cortex in aging

Objective To explore the regional and lateral differences of adult cerebral cortex volume, thickness and surface area during normal aging by MRI.Methods The prospective study was conducted. From September 2017 to January 2018, 109 healthy adult volunteers of right-handed Han nationality were recruited, including 56 males and 53 females, average age (53.13±15.61) years (aged 18-85 years). The original data of 3.0 T MRI were obtained and analyzed with FreeSurfer software to obtain the interesting areas of left and right hemispheres and lobes. The specific values of the volume, including thickness and surface area of the regional cerebral cortex were studied to explore the correlation with age, the regional and lateral differences of cerebral cortex aging.Results Linear regression analysis showed age-related decreases in global cortical volume, thickness and surface area (P＜0.01). The largest age-related decreases in cortical volume were in the middle frontal gyrus, inferior frontal gyrus, inferior parietal angular gyrus, lingual gyrus, middle temporal gyrus and parahippocampal gyrus(the largest was -0.653% per year, P＜0.01). The areas with the greatest decrease in cortical thickness were the middle frontal gyrus, the frontal gyrus of outer orbit, the inferior parietal angular gyrus, the superior temporal gyrus, the temporal pole, the parahippocampal gyrus and the posterior cingulate gyrus(the largest was -0.009 mm per year, P＜0.01). The areas with the greatest decrease in cortical surface area were mainly in the middle frontal gyrus, the infra-frontal gyrus, the lingual gyrus, the inferior temporal gyrus and the parahippocampal gyrus (the largest was -0.40% per year, P＜0.01). The asymmetric regions of cortical volume-age effect in the left and right hemispheres were superior frontal gyrus, inferior frontal gyrus and triangle, middle orbital frontal gyrus, frontal pole, inferior parietal marginal angular gyrus, superior marginal gyrus, fusiform gyrus, temporal pole, parahippocampal gyrus, anterior cingulate gyrus and entorhinal cortex(P＜0.05). The asymmetric regions of age effect of cortical thickness were superior frontal gyrus, inferior frontal gyrus, middle orbital frontal gyrus, cuneate lobe, inferior temporal gyrus, temporal pole, anterior cingulate gyrus and posterior cingulate gyrus (P＜0.05). The asymmetric regions of age effect of cortical surface area were superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, trigone, frontal pole, inferior parietal angular gyrus, superior marginal gyrus, fusiform gyrus, temporal pole, parahippocampal gyrus, anterior cingulate gyrus, posterior cingulate gyrus and entorhinal cortex (P＜0.05).Conclusions In normal aging process of human brain, the volume, thickness and surface area of cerebral cortex show linear negative correlations with age. Aging has different effects in cortical regions. The age effect of partial gyri is lateralized. Three morphological indexes of cortical volume, thickness and surface area are interrelated.