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Open Imaging Index
MRI Brain

OASIS-1

OASIS-1: Cross-Sectional MRI Data in Young, Middle Aged, Nondemented and Demented Older Adults

Structural brain MRI of adults across the age range, including older adults with very mild to moderate Alzheimer's disease, commonly used to study brain volume changes with age and dementia. 416 people aged 18 to 96, 100 with dementia, with averaged images and tissue segmentations.

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Overview

OASIS-1 was the first release of the Open Access Series of Imaging Studies from Washington University in St. Louis, published in 2007. It provides structural brain MRI from one visit per person across the adult age range, covering young and middle-aged adults as well as older adults with and without Alzheimer's disease. It is commonly used to study brain volume changes with age and dementia and to develop and test segmentation and classification methods.

Composition

The set holds 416 right-handed subjects aged 18 to 96: 160 men and 256 women. 316 are nondemented and 100, all over 60, have a clinical diagnosis of probable Alzheimer's disease with a Clinical Dementia Rating of 0.5 (70 subjects), 1 (28) or 2 (2). A reliability subset of 20 nondemented subjects was scanned again within 90 days of the first session. The dataset page counts 434 MR sessions in total. A spreadsheet lists sex, handedness, age, education, socioeconomic status, MMSE, CDR and three derived anatomic measures: estimated total intracranial volume, atlas scaling factor and normalized whole-brain volume.

Acquisition

Each session contains 3 or 4 repeated T1-weighted acquisitions of the same structural protocol, stored sagittally at 1 x 1 x 1.25 mm. The repetitions were combined into a motion-corrected average, which was then gain-field corrected and registered to the Talairach and Tournoux atlas space at 1 mm isotropic resolution, with and without a brain mask. Faces were removed before release. All images are in Analyze 7.5 format, about 15.8 GB compressed. FreeSurfer outputs are offered as a separate download.

Annotations

There are no manual labels. Each session includes an automated grey matter, white matter and CSF segmentation of the masked atlas-registered image, and the clinical diagnosis and CDR serve as labels for classification.

Known limitations

  • Cross-sectional design: apart from the 20 reliability subjects, each person has a single session.
  • Dementia cases are limited to subjects over 60, and the under-60 range is dominated by people in their twenties (119 of 416).
  • Scanner model and field strength are not stated on the dataset page or in the fact sheet.
  • The OASIS team advises against pooling OASIS-1 with OASIS-2 or OASIS-3.

Cohort

Aggregate numbers from the sources below. Bars are relative to the 416 subjects.

Sex

  • Female 256 62%
  • Male 160 38%

Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)

Contrast / sequence

Groups can overlap

  • T1-weighted 416 100%

Abstract in Marcus et al. 2007, Journal of Cognitive Neuroscience (abstract)

Age by condition

Reported cross table. A dot marks a cell the source does not give.

Healthy controlAlzheimer's disease
0-1919·
20-29119·
30-3916·
40-4931·
50-5933·
60-692515
70-793548
80-893032
90+85

Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)

Age

range 18 to 96

0
50
100
119
0-1920-2930-3940-4950-5960-6970-7980-8990+

Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20); Abstract in Marcus et al. 2007, Journal of Cognitive Neuroscience (abstract)

Condition

Groups can overlap

  • Healthy control 316 76%
  • Alzheimer's disease 100 24%

Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)

Condition by sex

Reported cross table. A dot marks a cell the source does not give.

FemaleMale
Healthy control197119
Alzheimer's disease5941

Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)

Contrast combinations

How many subjects have exactly each set of contrasts.

T1wSubjects with exactly this set
416

Abstract in Marcus et al. 2007, Journal of Cognitive Neuroscience (abstract)

Other reported numbers 26
Subjects · Healthy control, Male, 0-19 10Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 0-19 9Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 20-29 51Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 20-29 68Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 30-39 11Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 30-39 5Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 40-49 10Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 40-49 21Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 50-59 11Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 50-59 22Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 60-69 7Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 60-69 18Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 70-79 10Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 70-79 25Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 80-89 8Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 80-89 22Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Male, 90+ 1Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Healthy control, Female, 90+ 7Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Male, 60-69 6Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Female, 60-69 9Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Male, 70-79 20Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Female, 70-79 28Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Male, 80-89 13Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Female, 80-89 19Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Male, 90+ 2Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)
Subjects · Alzheimer's disease, Female, 90+ 3Table 2 in OASIS Fact Sheet, Cross-Sectional Data Across the Adult Lifespan (rev. 2007-8-20)

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
Open download

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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 OASIS access page states that all OASIS data are distributed under these terms, but the OASIS-1 archives download directly from the dataset page without an access request.

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

What you can do

  • No
  • Not stated
  • 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, Wang TH, Parker J, Csernansky JG, Morris JC, Buckner RL. Open Access Series of Imaging Studies (OASIS): Cross-Sectional MRI Data in Young, Middle Aged, Nondemented, and Demented Older Adults. Journal of Cognitive Neuroscience 19, 1498-1507 (2007). doi:10.1162/jocn.2007.19.9.1498

Sources

Every number on this page comes from one of these documents. Each chart names the table or page it is taken from. The raw numbers are in stats.csv.