PDF(Pubmed)
Abstract：
Brain atrophy and cortical thinning are typically observed in people with Alzheimer\'s disease (AD) and, to a lesser extent, in those with mild cognitive impairment. In asymptomatic middle-aged apolipoprotein ε4 (ΑPOE4) carriers, who are at higher risk of future AD, study reports are discordant with limited evidence of brain structural differences between carriers and non-carriers of the ε4 allele. Alternative imaging markers with higher sensitivity at the presymptomatic stage, ideally quantified using typically acquired structural MRI scans, would thus be of great benefit for the detection of early disease, disease monitoring and subject stratification. In the present cross-sectional study, we investigated textural properties of T1-weighted 3T MRI scans in relation to APOE4 genotype, age and sex. We pooled together data from the PREVENT-Dementia and ALFA studies focused on midlife healthy populations with dementia risk factors (analysable cohort: 1585 participants; mean age 56.2 ± 7.4 years). Voxel-based and texture (examined features: contrast, entropy, energy, homogeneity) based morphometry was used to identify areas of volumetric and textural differences between APOE4 carriers and non-carriers. Textural maps were generated and were subsequently harmonised using voxel-wise COMBAT. For all analyses, APOE4, sex, age and years of education were used as model predictors. Interactions between APOE4 and age were further examined. There were no group differences in regional brain volume or texture based on APOE4 carriership or when age × APOE4 interactions were examined. Older people tended to have a less homogeneous textural profile in grey and white matter and a more homogeneous profile in the ventricles. A more heterogeneous textural profile was observed for females in areas such as the ventricles, frontal and parietal lobes and for males in the brainstem, cerebellum, precuneus and cingulate. Overall, we have shown the absence of volumetric and textural differences between APOE4 carriers and non-carriers at midlife and have established associations of textural features with ageing and sex.
摘要：
脑萎缩和皮质变薄通常在患有阿尔茨海默病（AD）的人中观察到，在较小程度上，轻度认知障碍患者。在无症状的中年载脂蛋白ε4（APOE4）携带者中，未来AD的风险更高，研究报告与ε4等位基因携带者和非携带者之间大脑结构差异的有限证据不一致。在症状前阶段具有更高灵敏度的替代成像标记，使用通常获得的结构MRI扫描进行理想量化，因此对早期疾病的检测非常有益，疾病监测和受试者分层。在目前的横断面研究中，我们调查了T1加权3TMRI扫描的结构特性与APOE4基因型的关系，年龄和性别我们汇集了来自PREVENT-Dementia和ALFA研究的数据，这些研究集中于具有痴呆危险因素的中年健康人群（可分析队列：1585名参与者；平均年龄56.2±7.4岁）。基于体素和纹理(检查的特征：对比度，熵,能源,基于同质性）的形态计量学用于识别APOE4携带者和非携带者之间的体积和纹理差异区域。生成纹理图，然后使用逐体素COMBAT进行协调。对于所有分析，APOE4性别,年龄和受教育年限被用作模型预测因子。进一步检查了APOE4与年龄之间的相互作用。根据APOE4载体或检查年龄×APOE4相互作用时，区域脑体积或质地没有组间差异。老年人倾向于在灰质和白质中具有较不均匀的纹理轮廓，而在心室中具有较均匀的轮廓。女性在心室等区域观察到了更不均匀的质地轮廓，额叶和顶叶，男性在脑干，小脑,precuneus和扣带回。总的来说,我们已经表明，在中年时，APOE4携带者和非携带者之间没有体积和质地差异，并且已经建立了质地特征与年龄和性别的关联。
