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Open Imaging Index
MRI Brain

OASIS-2

Open Access Series of Imaging Studies (OASIS): Longitudinal MRI Data in Nondemented and Demented Older Adults

Longitudinal brain MRI of 150 right-handed adults aged 60 to 96, nondemented or with very mild to mild Alzheimer's disease, scanned at two or more visits (373 sessions) with 3 or 4 T1-weighted MP-RAGE scans per session at 1.5 T.

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Overview

OASIS-2 is the second release of the Open Access Series of Imaging Studies, also called OASIS Longitudinal. It contains repeated structural brain MRI of older adults from the longitudinal pool of the Washington University Alzheimer Disease Research Center, and is used to study brain volume loss in normal ageing and early Alzheimer's disease and to develop and test morphometry tools.

Composition

There are 150 right-handed participants (88 women, 62 men) aged 60 to 96 at entry, each scanned on two or more visits (on average 719 days apart), for 373 imaging sessions. Dementia status was staged with the Clinical Dementia Rating (CDR). 72 participants stayed nondemented throughout, 64 had a CDR above 0 at their first visit and 14 converted from CDR 0 to dementia at a later visit. Each session holds 3 or 4 individual T1-weighted scans. Age, sex, education, socioeconomic status, MMSE, CDR, estimated intracranial volume, atlas scaling factor and normalized whole-brain volume come as a spreadsheet. Many participants also appear in OASIS-1 under different identifiers.

Acquisition

All sessions were acquired on the same 1.5 T Siemens Vision scanner with an unchanged MP-RAGE protocol (sagittal, 1.25 mm slices, 1 x 1 mm in-plane). Images are distributed as NIfTI. Besides the raw scans, each session includes the motion-corrected average, a bias-corrected image registered to the Talairach atlas, and a brain-masked version.

Annotations

No manual labels. Each session comes with an automated grey matter, white matter and CSF segmentation in atlas space, and the clinical CDR rating per visit.

Known limitations

  • A single scanner and a single T1-weighted sequence: no FLAIR, T2 or other contrasts.
  • The images were not defaced. The OASIS terms forbid any use that could reconstruct or recognise faces.
  • Exclusion of non-Alzheimer dementias, stroke and large lesions makes the cohort cleaner than a clinical population.
  • 25 sessions were dropped for poor quality; some borderline scans remain.
  • The paper gives 51 participants with CDR 0.5 at entry in the text and Table 3, but 52 in Table 2.
  • The 2010 paper describes the usage policy as liberal; current access goes through the OASIS data use agreement.

Cohort

Aggregate numbers from the sources below. Bars are relative to the 150 subjects.

Sex

  • Female 88 59%
  • Male 62 41%

Age

ยท range 60 to 96
0
20
40
60
71
60-6970-7980-8990-99

Age by sex

Reported cross table. Missing cells were not published (fewer than 10 subjects or not reported).

Female Male
  • 3
    90-99
    1
  • 25
    80-89
    16
  • 40
    70-79
    31
  • 20
    60-69
    14

Contrast combinations

How many subjects have exactly each set of contrasts.

T1wSubjects with exactly this set
150

Contrast / sequence

subjects, values can overlap

  • T1-weighted 150 100%

Condition

subjects, values can overlap

  • Alzheimer's disease 78 52%
  • Healthy control 72 48%

Scanner vendor

subjects

  • Siemens Healthineers 150 100%

Field strength

subjects

  • 1.5 T 150 100%

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.

The access form lists OASIS-2 among the open OASIS datasets and states that country restrictions do not apply to it.

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

Marcus DS, Fotenos AF, Csernansky JG, Morris JC, Buckner RL. Open Access Series of Imaging Studies: Longitudinal MRI Data in Nondemented and Demented Older Adults. Journal of Cognitive Neuroscience 22(12), 2677-2684 (2010). doi:10.1162/jocn.2009.21407

All numbers

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

MeasureBreakdownValueSource
Subjectstotal 150marcus2010
Abstract; Table 2
Studiestotal
MR imaging sessions; each subject has two or more visits
373marcus2010
Abstract; Methods (Subjects)
Subjectscondition=healthy
nondemented (CDR 0) at every visit
72marcus2010
Abstract; Table 3 note
Subjectscondition=alzheimers
sum of two disjoint groups: 64 with CDR above 0 at the initial visit and 14 who converted from CDR 0 at a later visit
78marcus2010
Abstract; Table 2
Subjectssex=female 88marcus2010
Abstract; Table 2
Subjectssex=male 62marcus2010
Abstract; Table 2
Subjectsage=60-69
age at initial visit
34marcus2010
Table 2
Subjectsage=70-79
age at initial visit
71marcus2010
Table 2
Subjectsage=80-89
age at initial visit
41marcus2010
Table 2
Subjectsage=90-99
age at initial visit
4marcus2010
Table 2
Subjectssex=female;age=60-69
age at initial visit; sum of the disjoint nondemented (17) and demented (3) columns
20marcus2010
Table 2
Subjectssex=male;age=60-69
age at initial visit; sum of the disjoint nondemented (6) and demented (8) columns
14marcus2010
Table 2
Subjectssex=female;age=70-79
age at initial visit; sum of the disjoint nondemented (24) and demented (16) columns
40marcus2010
Table 2
Subjectssex=male;age=70-79
age at initial visit; sum of the disjoint nondemented (11) and demented (20) columns
31marcus2010
Table 2
Subjectssex=female;age=80-89
age at initial visit; sum of the disjoint nondemented (17) and demented (8) columns
25marcus2010
Table 2
Subjectssex=male;age=80-89
age at initial visit; sum of the disjoint nondemented (9) and demented (7) columns
16marcus2010
Table 2
Subjectssex=female;age=90-99
age at initial visit; sum of the disjoint nondemented (2) and demented (1) columns
3marcus2010
Table 2
Subjectssex=male;age=90-99
age at initial visit; sum of the disjoint nondemented (0) and demented (1) columns
1marcus2010
Table 2
Subjectscontrast=T1w
3 to 4 T1-weighted MP-RAGE scans per session
150marcus2010
Methods (Image Acquisition)
Subjectscontrast_set=T1w
T1-weighted MP-RAGE is the only sequence
150marcus2010
Methods (Image Acquisition)
Subjectsfield_strength=1.5
all sessions on one 1.5 T Siemens Vision scanner
150marcus2010
Methods (Image Acquisition)
Subjectsvendor=siemens 150marcus2010
Methods (Image Acquisition)
Minimum agetotal 60marcus2010
Abstract
Maximum agetotal 96marcus2010
Abstract

Sources

The keys used in the table above.