Louvain Aging Brain Lab, Institute of Neuroscience, UCLouvain, Brussels, Belgium.
Nuclear Medicine Department, Saint-Luc University Hospital, Brussels, Belgium.
Alzheimers Dement. 2024 Oct;20(10):7205-7219. doi: 10.1002/alz.14235. Epub 2024 Sep 10.
Magnetic resonance imaging (MRI) segmentation algorithms make it possible to study detailed medial temporal lobe (MTL) substructures as hippocampal subfields and amygdala subnuclei, offering opportunities to develop biomarkers for preclinical Alzheimer's disease (AD).
We identified the MTL substructures significantly associated with tau-positron emission tomography (PET) signal in 581 non-demented individuals from the Alzheimer's Disease Neuroimaging Initiative (ADNI-3). We confirmed our results in our UCLouvain cohort including 110 non-demented individuals by comparing volumes between individuals with different visual Braak's stages and clinical diagnosis.
Four amygdala subnuclei (cortical, central, medial, and accessory basal) were associated with tau in amyloid beta-positive (Aβ+) clinically normal (CN) individuals, while the global amygdala and hippocampal volumes were not. Using UCLouvain data, we observed that both Braak I-II and Aβ+ CN individuals had smaller volumes in these subnuclei, while no significant difference was observed in the global structure volumes or other subfields.
Measuring specific amygdala subnuclei, early atrophy may serve as a marker of temporal tauopathy in preclinical AD, identifying individuals at risk of progression.
Amygdala atrophy is not homogeneous in preclinical Alzheimer's disease (AD). Tau pathology is associated with atrophy of specific amygdala subnuclei, specifically, the central, medial, cortical, and accessory basal subnuclei. Hippocampal and amygdala volume is not associated with tau in preclinical AD. Hippocampus and CA1-3 volume is reduced in preclinical AD, regardless of tau.
磁共振成像（MRI）分割算法使研究内侧颞叶（MTL）亚结构（如海马亚区和杏仁核亚核）成为可能，为开发临床前阿尔茨海默病（AD）的生物标志物提供了机会。
我们在来自阿尔茨海默病神经影像学倡议（ADNI-3）的 581 名非痴呆个体中确定了与tau-正电子发射断层扫描（PET）信号显著相关的 MTL 亚结构。我们通过比较不同视觉 Braak 阶段和临床诊断个体之间的体积，在包括 110 名非痴呆个体的 UCLouvain 队列中证实了我们的结果。
在 Aβ+临床正常（CN）个体中，四个杏仁核亚核（皮质、中央、内侧和辅助基底）与 tau 相关，而杏仁核和海马体体积不相关。使用 UCLouvain 数据，我们观察到 Braak I-II 和 Aβ+CN 个体在这些亚核中体积较小，而在整体结构体积或其他亚区中没有观察到显著差异。
测量特定的杏仁核亚核，早期萎缩可能是临床前 AD 中颞叶 tau 病的标志物，可识别有进展风险的个体。
在临床前 AD 中，杏仁核萎缩不是均匀的。tau 病理学与特定杏仁核亚核的萎缩有关，特别是中央、内侧、皮质和辅助基底亚核。在临床前 AD 中，海马体和杏仁核体积与 tau 无关。在临床前 AD 中，无论 tau 如何，海马体和 CA1-3 体积都会减少。
