The Alzheimer’s Disease Neuroimaging Initiative (ADNI) began in 2004 as longitudinal multicenter study to identify clinical, imaging, genetic, and biochemical biomarkers for the detection and tracking of Alzheimer’s disease (AD). Participants are recruited from and followed at 59 research sites in the United States and Canada.

• ADNI1 enrolled 400 subjects who were diagnosed with mild cognitive impairment (MCI), 200 subjects with early AD, and 200 elderly control subjects. Data collected included MRI and PET brain scans, genetic profiles, and blood and cerebrospinal fluid biomarkers.
• ADNI GO began in 2009 and included all ADNI1 participants and enrolled 200 new participants with early mild cognitive impairment (EMCI).
• ADNI2 began in 2011 and recruited an additional 150 elderly control subjects, 100 ECMI subjects, 150 late mild cognitive impairment (LMCI) subjects, and 150 subjects with mild AD. ADNI2 also added a new cohort group, Significant Memory Concern (SMC), and enrolled 107 subjects with self-reported significant memory concerns. During this phase, collection of amyloid PET with Florbetapir was added to study protocols at all ADNI2 sites for all ADNI2 and ADNI GO subjects.
• ADNI3 began in 2016 with an anticipated enrollment of 150-515 new MCI subjects, 85-185 mild AD subjects, and 135-500 elderly control subjects. ADNI3 data includes longitudinal tau PET scans with AV 1451 and brain scans that detect tau protein tangles (tau PET).