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Open Imaging Index
MRI Brain

PPG (USC P01 neurovascular cohort)

Vascular Contributions to Dementia and Genetic Risk Factors for Alzheimer's Disease (PPG, NIH P01 AG052350)

Brain MRI with dynamic contrast-enhanced imaging of blood-brain barrier leakage in older adults who are cognitively unimpaired or mildly impaired, collected to test whether vascular dysfunction drives early cognitive decline in APOE4 carriers. Held on LONI IDA without a public application.

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Overview

The PPG cohort comes from a National Institute on Aging program project grant (P01 AG052350) led from the University of Southern California. It asks whether damage to the brain's blood vessels, in particular leakage of the blood-brain barrier, comes before and predicts cognitive decline, and whether this happens earlier in carriers of the APOE4 risk gene. Participants were recruited through the USC Alzheimer's Disease Research Center, the Washington University Knight ADRC and an APOE cohort at Banner Alzheimer's Institute and Mayo Clinic Arizona. Imaging is archived in a private project on the LONI Image and Data Archive (IDA).

Composition

The 2022 grant renewal states that 510 participants were enrolled in the first funding period. Participants are 45 or older and cognitively unimpaired or mildly impaired. The renewal planned to follow 402 APOE4 carriers and 465 APOE3 homozygotes, including 360 new recruits; that target is a plan, not an enrolled count. In the 2020 Nature analysis, 435 participants had clinical and neuropsychological exams, 350 a lumbar puncture and 245 a DCE-MRI. Clinical data follow the Uniform Data Set and include the CDR score and APOE genotype.

Acquisition

In the 2020 analysis, MRI came from Siemens 3 T scanners with a mirrored protocol: a Prisma at USC, and an mMR and a Vida at Washington University. DCE-MRI covers the hippocampi and temporal lobes with a T1-weighted VIBE sequence over 16 minutes after 0.05 mmol/kg gadoterate, preceded by variable flip angle T1 mapping and a coronal T2-weighted scan. A 3D T1-weighted MPRAGE is acquired as well. A USC subset has resting-state fMRI on a TrioTim. The grant also names diffusion, arterial spin labeling and DSC perfusion MRI, and amyloid and tau PET were acquired in subsets; whether these series are on IDA is not stated.

Known limitations

No public description of the IDA release exists, and there is no public application process, so all counts come from analysis papers or the grant record. Samples in the papers are mostly white, with about 16 to 17 years of education on average. Several papers pool PPG data with other USC cohorts.

Cohort

Aggregate numbers from the sources below. Bars are relative to the 510 subjects.

Contrast / sequence

Groups can overlap

  • DCE perfusion 245 48%
  • BOLD fMRI 89 17%

Methods, Study Participants in Montagne A et al. 2020, APOE4 leads to blood-brain barrier dysfunction predicting cognitive decline, Nature (author manuscript PMC7250000); Methods, Participants; Table 1 in Contreras JA et al. 2024, Decreased functional connectivity is associated with increased levels of CSF soluble-PDGFRβ in older adults, Brain Imaging and Behavior

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
On request

Ask the authors or the data holder. No published process or terms, and access is at their discretion

Access page

No published license or data use terms

The data holder has published no license and no data use terms. Any use, sharing or commercial right has to be agreed with the data holder, and nothing can be assumed to be allowed. Default copyright and data protection law still apply.

PPG is a private project on the LONI Image and Data Archive. It is not in the public list of studies one can apply to, and its application page requires a login. Program papers state that data are available from the corresponding author on reasonable request.

Original license text Checked 2026-10-08

What you can do

  • Commercial use Not stated
  • Not stated
  • Train ML models Not stated
  • Create derived data Not stated
  • Publish results Not stated

What you can share

  • Share the data Not stated
  • Share derived data Not stated
  • Share trained models Not stated

What you must do

  • Cite or credit Not stated
  • Share alike Not stated
  • Sign an agreement Not stated
  • Ethics approval Not stated
  • Manuscript review Not stated
  • Release code Not stated
  • Return results Not stated
  • Delete after use Not stated

Limits

  • No re-identification Not stated
  • Location limits Not stated

Citation

Montagne A, Nation DA, Sagare AP, et al. APOE4 leads to blood-brain barrier dysfunction predicting cognitive decline. Nature 581(7806):71-76 (2020). doi:10.1038/s41586-020-2247-3

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.