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Open Imaging Index
MRI Brain

OASIS-4

OASIS-4: Clinical Cohort

Clinical cohort of 663 people aged 21 to 94 evaluated for memory disorders and dementia at Washington University in St. Louis, with 676 MR sessions plus clinical, CSF and neuropsychological data. Separate from OASIS-3.

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Overview

OASIS-4 is the fourth release of the Open Access Series of Imaging Studies from Washington University in St. Louis. It is a clinical cohort of people who were assessed for memory problems and dementia, and it stands on its own: it is not a newer version of OASIS-3. Each participant comes with clinical, cerebrospinal fluid and neuropsychological data next to the brain MRI.

Composition

The project page lists 663 subjects between 21 and 94 years old and 676 MR sessions, only 13 more sessions than subjects. Demographic, clinical, CSF and psychometric spreadsheets are provided as separate data files within the project. The reference publication drew its Clinical Cohort from patients of the Washington University Memory Diagnostic Center, an outpatient memory clinic, and described that cohort as soon to be released as OASIS-4. Its diagnoses included Alzheimer disease and several non-Alzheimer causes of cognitive complaints.

Acquisition

In the reference publication, the memory clinic patients had their MRI as part of the diagnostic evaluation for dementia. The data are hosted on the NITRC Image Repository and can be downloaded with the official OASIS scripts, which convert the scans with dcm2niix to NIfTI in a BIDS layout (BIDS version 1.0.1) with JSON sidecars. Scanner models, field strengths and the list of sequences are not published for this release.

Annotations

No manual labels. MR sessions come with FreeSurfer post-processing outputs.

Known limitations

  • No data descriptor exists. The reference publication analyses a 579-patient precursor of the cohort, not the released set, so its numbers are not repeated here.
  • Sex, diagnosis and scanner breakdowns of the released cohort are not published.

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

OASIS Data Use Agreement

Non-commercial academic research only, after an application reviewed by OASIS staff. No sharing with anyone, collaborators included, without written permission; data must be destroyed or returned when the research ends. Publications must acknowledge OASIS, and work using AV45 or AV1451 PET must go to Avid Radiopharmaceuticals for review 30 days in advance.

Original license text Version read: OASIS Data Use Agreement Terms, July 2025 Checked 2026-10-07

What you can do

  • No
  • Not stated
  • Conditional
  • Conditional

What you can share

  • No
  • Not stated
  • Share trained models Not stated

What you must do

  • Yes
  • Share alike No
  • Yes
  • Ethics approval No
  • Conditional
  • Release code No
  • No
  • Yes

Limits

  • Yes
  • No

Commercial license: Conditional Commercial use needs explicit, prior written authorization from OASIS. No commercial license offer is published.

Citation

Koenig LN, Day GS, Salter A, et al. Select Atrophied Regions in Alzheimer disease (SARA): An improved volumetric model for identifying Alzheimer disease dementia. NeuroImage: Clinical 26, 102248 (2020). doi:10.1016/j.nicl.2020.102248

All numbers

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

MeasureBreakdownValueSource
Subjectstotal 663oasis4-page
Studiestotal
MR sessions; MRI is the only imaging modality listed
676oasis4-page
Minimum agetotal
age range given for all subjects
21oasis4-page
Maximum agetotal 94oasis4-page

Sources

The keys used in the table above.