早发型阿尔茨海默病的影像学特点

Imaging characteristics of early-onset Alzheimer's disease

阿尔茨海默病(Alzheimer's disease,AD)是一种进行性加重、不可逆转的神经退行性疾病,其患病率随着人口年龄的增长而迅速增长。绝大多数AD患者的发病年龄在65岁之后,与此类常见的晚发型阿尔茨海默病(late-onset Alzheimer's disease,LOAD)相比,约有5%~10%的AD患者在65岁之前出现认知障碍的症状,被定义为早发型阿尔茨海默病(early-onset Alzheimer's disease,EOAD)。尽管LOAD、典型遗忘型EOAD及非典型EOAD有着相同的分子病理学,即淀粉样蛋白-β(Aβ)和tau的积累,但在临床表现上存在异质性。EOAD经常因非典型临床表现导致误诊或延迟诊断,且通常病情进展迅速,生存时间短,因此了解EOAD的特征对早期诊断和治疗尤为重要。不同临床表型的AD似乎在某些脑区存在选择性脆弱性,这可能为解释这种异质性提供了一个方向。本篇综述分析比较了近年来典型遗忘型及非典型EOAD结构、功能及分子成像的最新研究进展,探索影像学指标作为一种无创标志物的可行性及有效性,以期为EOAD诊断提供一些新思路。

Alzheimer's disease(AD)is a progressive irreversible neurodegenerative disease,and its prevalence rate is increasing rapidly as the population ages.Most patients with AD are diagnosed after the age of 65 years,and compared with late-onset Alzheimer's disease(LOAD),approximately 5%~10%of patients with AD develop cognitive impairment before the age of 65 years and are defined as early-onset Alzheimer's disease(EOAD).Although LOAD,typical amnestic EOAD,and atypical EOAD share the same molecular pathology of the accumulation ofβ-amyloid and tau,they tend to have heterogeneous clinical manifestations.EOAD is frequently misdiagnosed or delayed due to atypical clinical manifestations,and it often has rapid progression and a short survival time;therefore,it is crucial to understand the characteristics of EOAD for early diagnosis and treatment.Different clinical phenotypes of AD appear to have selective vulnerability in certain brain regions,which may help to explain such heterogeneity.This review analyzes the recent research advances in the structural,functional,and molecular imaging of typical amnestic EOAD and atypical EOAD and investigates the feasibility and effectiveness of imaging indicators as a noninvasive marker,so as to provide new ideas for the diagnosis of EOAD.