ADNI（Alzheimer`s disease neuroimaging initiative）介绍

第一部分：

ADNI数据库则是一个庞大的公开数据集，收集了最终被诊断出患有阿尔茨海默症、轻度认知障碍或没有任何障碍的患者的PET扫描数据。

以上内容来自：https://xw.qq.com/partner/hwbrowser/20190108A0PR3B/20190108A0PR3B00?ADTAG=hwb&pgv_ref=hwb&appid=hwbrowser&ctype=news

第二部分：

http://adni.loni.usc.edu

阿尔茨海默病神经影像学倡议（ADNI）是一项纵向多中心研究，旨在开发临床、影像、遗传和生化生物标记物，用于早期检测和跟踪阿尔茨海默病（AD）。

目标：1. AD的早诊，在pre-dementia之前的诊断，发现可用于跟踪疾病进展的marker；

　　    2. 在AD的早期，运用新的治疗方法来干预、诊断和治疗AD；

　　    3. 数据共享

ADNI已经报道了下面的这些发现：

1. 在病人还未出现记忆丧失标志前，AD的病理已经出现了，并且这些人（认知正常）有轻微的脑萎缩；

2. AD病人有一些典型特征：淀粉样蛋白沉积、葡萄糖代谢下降、大脑的结构变化；

3. 认知下降与tau的沉积更相关，相比Aβ；

4.大脑连接体逐渐破坏是AD的特征。随着疾病进展，大脑重要区域的连接越来越少；

5.除了APOE4，许多基因导致了AD。从目前发现的20个基因中，ADNI的数据发现/确认了其中的10个基因；

6.脑血管的疾病能够加速AD的进展；

7.认知正常和轻度认知损伤群体在病理上存在异质性。一些人没有发病，一些人很快出现了AD症状，一些人出现了痴呆而不是AD。

Biomarker是生物状态的一种标记。ADNI用多种marker来预测AD的发病。

　　1.检测脑脊液的Aβ或者通过 amyloid PET imaging；

　　2.检测脑脊液中的tau蛋白或着用FDG-PET测量的突触功能障碍，来检测神经退行性病变；

　　3.用核磁扫描检测脑萎缩，通常是medial temporal lobe内侧颞叶区域；

　　4.通过认知测试来检测记忆丢失；

　　5.通过认知测试评估认知下降的临床指标。

　前3种在痴呆之前就可以检测到；后2种是经典的痴呆诊断标准。

1. b-amyloid (A?) measured in cerebrospinal fluid or by amyloid PET imaging
2. Neurodegeneration indicated by tau protein measured in cerebrospinal fluid, or by synaptic dysfunction, measured by FDG-PET
3. Brain atrophy, mostly in the medial temporal lobe, measured by structural MRI
4. Memory loss, measured by cognitive tests
5. Clinical function, indicated by general cognitive decline measured by cognitive tests.

Changes 1-3 are indicated by biomarkers that can be observed prior to a dementia diagnosis, while changes 4-5 are the classic indicators of dementia diagnosis.

The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is a longitudinal multicenter study designed to develop clinical, imaging, genetic, and biochemical biomarkers for the early detection and tracking of Alzheimer’s disease (AD). Since its launch more than a decade ago, the landmark public-private partnership has made major contributions to AD research, enabling the sharing of data between researchers around the world.

Three overarching goals of the ADNI study are:

1. To detect AD at the earliest possible stage (pre-dementia) and identify ways to track the disease’s progression with biomarkers.
2. To support advances in AD intervention, prevention, and treatment through the application of new diagnostic methods at the earliest possible stages (when intervention may be most effective).
3. To continually administer ADNI’s innovative data-access policy, which provides all data without embargo to all scientists in the world.

Studies using ADNI cross-sectional and longitudinal data from multiple modalities have reported that:

• AD pathology is already present in people with no outward sign of memory loss and these cognitively normal people may already have subtle brain atrophy
• There are typical patterns of amyloid deposition, declines in glucose metabolism, and structural brain changes that occur in AD
• Cognitive decline is more closely linked to tau then Aß deposition
• AD is characterized by the progressive disruption of the brain connectome. As the disease progresses, there are fewer connections between essential brain regions.
• Many genes in addition to APOE4 underlie AD. ADNI data has helped to identify or confirm 10 of the approximately 20 genes currently identified
• Cerebrovascular disease can accelerate disease progression in AD
• Both the cognitively normal and MCI groups are pathologically heterogeneous. Some people show no signs of AD, some show signs of progressing to AD quickly, and others show signs of progressing to dementias other than AD