正常成年人脑体积随年龄变化的磁共振成像定量分析

目的探讨磁共振成像(MRI)测量正常成年人脑体积与年龄之间的关系。方法对150名正常成年人(18~83岁)行三维T1加权成像扫描,通过自动测量方法获得颅内腔容积、全脑体积、脑灰质(GM)、脑白质(WM)以及脑脊液(CSF)体积,然后进行标准化处理。结果MRI测得的成年人脑体积随年龄表现出不同的变化模式。颅内腔容积随年龄变化不明显;全脑体积在30岁前变化无显著性,之后随年龄减少;GM体积与年龄呈负相关关系;CSF体积与年龄呈正相关关系;WM体积和GM/WM与年龄均呈二次方改变模式,WM体积在45岁前随年龄呈缓慢增加,之后减小,而GM/WM在55岁前随年龄呈快速减小,之后缓慢增加。不同性别间颅内腔容积、全脑体积差异均有显著性(P<0·05),但标准化处理后全脑体积、GM、WM和CSF体积差异均无显著性。结论应用MRI能够测量正常成年人脑体积,其结果显示了正常成年人颅内腔容积、全脑体积、GM、WM和CSF体积随年龄的变化模式,有助于对异常脑体积的评价。

Quantitative analysis of brain volume by in vivo magnetic resonance imaging in normal adults

Objective To quantify neuroanatomical parameters with magnetic resonance imaging (MRI) and to explore the relationship between these parameters and age. Methods Totally 150 healthy adults aged 18-83 years received 3D fast spoiled gradient echo imaging. Volume of intracranial space, whole brain, gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) were measured and normalized. Results Normative volumetric estimates were obtained for all subjects and presented by age and sex. There was not significantly age-related change in intracranial space volume. Whole brain volume did not significantly change before 30 years,thereafter,decline with age. GM volume decreased linearly with age. CSF volume increased linearly with age. WM volume and GM/WM ratio demonstrated a quadratic pattern of change with age. WM volume increased slightly in subjects until the age of 45 years,and it decreased thereafter. However,GM/WM ratio decreased quickly in subjects until the age of 55 years,and it decreased slightly thereafter. Although the volumes of intracranial space and whole brain had significant differences between male and female(P<0.05), the volumes of whole brain, GM, and CSF had no significant differences after normalization. Conclusion In vivo MRI can measure the normal patterns of age- and sex-related changes in intracranial space, whole brain, GM, WM, and CSF, and may facilitate the appraisal of abnormal brain volumes.