The hippocampus is one of the first regions to demonstrate atrophy during the prodromal stage of Alzheimer's disease. Volumetric analysis of its individual subfields could provide biomarkers with higher sensitivity than whole hippocampal volume during an earlier disease stage. We quantified the hippocampal subfields volume in a large cohort comprising healthy participants (aged 40-59) with dementia family history (FH) and controls (without FH), examined at 2 time points across 2 years. Subfield volumes were quantified using both a T1-weighted and a high-resolution T2 hippocampal magnetic resonance imaging acquisition with Freesurfer. The participants were stratified based on dementia FH, APOE genotype, and CAIDE (Cardiovascular Risk Factors, Aging and Dementia) risk score. Whole hippocampal volume did not differ between the groups. The volume of the molecular layer was lower in participants with an APOE ε4 genotype, but there were no differences between subjects with and without dementia FH or with an increasing CAIDE score. The molecular layer may be the first hippocampal region to demonstrate volumetric alterations in subjects at risk of dementia.

中文翻译：

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痴呆风险增加的受试者海马亚区的体积变化

海马体是阿尔茨海默病前驱期最早出现萎缩的区域之一。在早期疾病阶段，对其各个子域的体积分析可以提供比整个海马体积更高的灵敏度的生物标志物。我们量化了一个大型队列中的海马亚区体积，该队列包括具有痴呆家族史 (FH) 的健康参与者（40-59 岁）和对照组（无 FH），在 2 年的 2 个时间点进行检查。使用 Freesurfer 的 T1 加权和高分辨率 T2 海马磁共振成像采集对子场体积进行量化。参与者根据痴呆 FH、APOE 基因型和 CAIDE（心血管危险因素、衰老和痴呆）风险评分进行分层。各组之间的整个海马体积没有差异。具有 APOE ε4 基因型的参与者的分子层体积较低，但患有和不患有痴呆 FH 或 CAIDE 评分增加的受试者之间没有差异。分子层可能是第一个在有痴呆风险的受试者中表现出体积变化的海马区域。