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Open Imaging Index
MRI PET Brain

ADNI

Alzheimer's Disease Neuroimaging Initiative (ADNI1, ADNI GO, ADNI2, ADNI3)

Longitudinal multi-site study in the US and Canada with repeated structural and advanced MRI, FDG, amyloid and tau PET, biofluids and cognitive testing of cognitively unimpaired older adults and people with MCI or Alzheimer's dementia.

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Overview

ADNI is a long-running observational study, run like a clinical trial, that tracks how imaging, fluid biomarkers and cognition change from normal ageing through mild cognitive impairment (MCI) to Alzheimer's dementia. It started in 2004 as a public-private partnership led by Michael Weiner. This entry covers the phases ADNI1, ADNI GO, ADNI2 and ADNI3; ADNI4 is ongoing.

Composition

A 2023 review counts 868 cognitively unimpaired participants, 1,090 with MCI and 408 with Alzheimer's dementia enrolled since 2004. Each phase added new people and kept many earlier ones: ADNI1 began with 819 people (229 controls, 398 MCI, 192 AD, mean age about 75), ADNI GO added an early MCI group and ADNI2 added a subjective memory concern group. Most have several imaging sessions. Clinical, cognitive, genetic and CSF/blood biomarker data come with the images.

Acquisition

More than 60 sites in the US and Canada take part, on GE, Philips and Siemens scanners with harmonised protocols. ADNI1 scanned everyone at 1.5 T (T1-weighted and dual-echo PD/T2), a quarter also at 3 T. From ADNI GO on, imaging moved to 3 T and added FLAIR and an axial T2*-weighted gradient echo (GRE) for microbleeds (ADNI3: 0.85 x 0.85 x 4 mm, TE 20 ms; a 3-echo version on Siemens). Diffusion, resting-state fMRI and ASL were added per vendor in ADNI2 and for nearly all participants in ADNI3. ADNI4 (outside this entry) adds a multi-echo GRE at capable sites, from which SWI is to be derived. PET started with FDG and a small PiB pilot, then used florbetapir for amyloid and, from ADNI3, flortaucipir for tau.

Annotations

There are no voxel-level labels. Mayo Clinic reads the GRE scans for cerebral microbleeds and superficial siderosis and releases each finding with its location (table MAYOADIRL_MRI_MCH). The MRI core reports 641 participants with one or more microbleeds and 57 with superficial siderosis in ADNI GO/2 and ADNI3. Diagnoses, cognitive scores, QC ratings, FreeSurfer volumes and amyloid and tau SUVRs are also released.

Known limitations

  • Diagnostic criteria and group names changed between phases (early/late MCI were merged again in ADNI3).
  • Scanner upgrades over the years can break longitudinal comparability; the MRI core advises treating data across hardware changes as incompatible.
  • Participants are mostly white and highly educated, which limits generalisability; ADNI4 aims to change this.
  • Sequences beyond T1, FLAIR and T2* are not available for all participants in ADNI2.

Cohort

Aggregate numbers from the sources below. Bars are relative to the 2,366 subjects.

Contrast / sequence

scans, values can overlap

  • T2*-weighted 6,752

Condition

subjects, values can overlap

  • Mild cognitive impairment 1,090 46%
  • Healthy control 868 37%
  • Cerebral microbleeds 641 27%
  • Alzheimer's disease 408 17%
  • Superficial siderosis 57 2%

License and access

Our reading of the license, not legal advice. Before you use the data, read the original license and confirm that your use is allowed. We take no responsibility for how you use a dataset. Full disclaimer

Access
Application

A research proposal is reviewed and approved

Access page

ADNI Data Use Agreement

Access for scientific investigation, teaching or planning clinical research after an online application. No redistribution of participant-level data, mandatory ADNI credit in the author line and a review of every manuscript by the ADNI Data and Publications Committee before journal submission. Model training is allowed but the data must not reach third-party AI services that retain inputs.

Original license text Version read: Current DUA with Appendix A on AI tools, PDF created 22 April 2026 Checked 2026-10-07

What you can do

  • Not stated
  • Conditional
  • Yes
  • Conditional

What you can share

  • No
  • Conditional
  • Conditional

What you must do

  • Yes
  • Share alike No
  • Yes
  • Conditional
  • Yes
  • Release code No
  • Conditional
  • Delete after use No

Limits

  • Yes
  • No

Citation

Add "for the Alzheimer's Disease Neuroimaging Initiative*" to the author line and use the methods and funding text given in the ADNI Data Use Agreement. Cohort reference: Petersen RC, et al. Alzheimer's Disease Neuroimaging Initiative (ADNI): clinical characterization. Neurology 74(3):201-209 (2010). doi:10.1212/WNL.0b013e3181cb3e25

All numbers

Every number on this page, as stored in stats.csv, with its source.

MeasureBreakdownValueSource
Subjectstotal
sum of the three baseline groups (868 CU + 1090 MCI + 408 AD) given in one sentence of the source; ADNI1 to ADNI3, as reported in 2023
2,366review2023
Section 1 (Introduction)
Subjectscondition=healthy
cognitively unimpaired participants enrolled and followed since 2004 (as reported in 2023)
868review2023
Section 1 (Introduction)
Subjectscondition=mci
enrolled and followed since 2004 (as reported in 2023)
1,090review2023
Section 1 (Introduction)
Subjectscondition=alzheimers
dementia diagnosed as AD; enrolled and followed since 2004 (as reported in 2023)
408review2023
Section 1 (Introduction)
Scanscontrast=T2starw
T2* GRE series received: 4302 in ADNI GO/2 and 2450 in ADNI3 (none in ADNI1); 6623 passed QC
6,752jack2024
Table 2
Subjectscondition=cerebral_microbleeds
one or more microbleeds on the Mayo Clinic GRE reads; ADNI GO/2 and ADNI3 only, as GRE was not acquired in ADNI1. The 56% in the table is of 1149 findings, not of participants
641jack2024
Table 3
Subjectscondition=superficial_siderosis
Mayo Clinic GRE reads; ADNI GO/2 and ADNI3 only. The 5% in the table is of 1149 findings, not of participants
57jack2024
Table 3

Sources

The keys used in the table above.