Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, United States.
Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, 18B Trumpington Road, Cambridge, England CB2 8AH, United Kingdom.
Neuroimage Clin. 2017 Nov 6;17:263-271. doi: 10.1016/j.nicl.2017.10.022. eCollection 2018.
People with Down syndrome (DS) develop Alzheimer's disease (AD) at higher rates and a younger age of onset compared to the general population. As the average lifespan of people with DS is increasing, AD is becoming an important health concern in this group. Neuroimaging is becoming an increasingly useful tool in understanding the pathogenesis of dementia development in relation to clinical symptoms. Furthermore, neuroimaging has the potential to play a role in AD diagnosis and monitoring of therapeutics. This review describes major recent findings from in vivo neuroimaging studies analysing DS and AD via ligand-based positron emission tomography (PET), [18F] fluorodeoxyglucose (FDG)-PET, structural magnetic resonance imaging (sMRI), and diffusion tensor imaging (DTI). Electroencephalography (EEG) and retinal imaging are also discussed as emerging modalities. The review is organized by neuroimaging method and assesses the relationship between cognitive decline and neuroimaging changes. We find that amyloid accumulation seen on PET occurs prior to dementia onset, possibly as a precursor to the atrophy and white matter changes seen in MRI studies. Future PET studies relating tau distribution to clinical symptoms will provide further insight into the role this protein plays in dementia development. Brain activity changes demonstrated by EEG and metabolic changes seen via FDG-PET may also follow predictable patterns that can help track dementia progression. Finally, newer approaches such as retinal imaging will hopefully overcome some of the limitations of neuroimaging and allow for detection of dementia at an earlier stage.
唐氏综合征（DS）患者患阿尔茨海默病（AD）的比率和发病年龄均高于普通人群。随着 DS 患者的平均寿命延长，AD 成为该人群的一个重要健康关注点。神经影像学在了解与临床症状相关的痴呆发展的发病机制方面正成为一种越来越有用的工具。此外，神经影像学有可能在 AD 诊断和治疗监测中发挥作用。本综述描述了通过配体正电子发射断层扫描（PET）、[18F]氟脱氧葡萄糖（FDG）-PET、结构磁共振成像（sMRI）和弥散张量成像（DTI）对 DS 和 AD 进行分析的最新体内神经影像学研究的主要发现。还讨论了脑电图（EEG）和视网膜成像等新兴模式。该综述按神经影像学方法进行组织，并评估认知能力下降与神经影像学变化之间的关系。我们发现，PET 上观察到的淀粉样蛋白积聚发生在痴呆发病之前，可能是 MRI 研究中观察到的萎缩和白质变化的前兆。未来将 tau 分布与临床症状相关联的 PET 研究将进一步深入了解该蛋白在痴呆发展中的作用。通过 EEG 显示的脑活动变化和 FDG-PET 观察到的代谢变化也可能遵循可预测的模式，有助于跟踪痴呆进展。最后，视网膜成像等新方法有望克服神经影像学的一些局限性，并更早地发现痴呆症。
