MRi-Share

MRi-Share is the brain imaging arm of i-Share, a French cohort study of student health coordinated from the University of Bordeaux. The Neurofunctional Imaging Group (GIN-IMN) scanned students from the Bordeaux site to describe how brain structure and function change in the late teens and twenties, to look for early markers of later-life disease, and to serve as an imaging data platform for other researchers. The protocol copies the UK Biobank brain imaging protocol closely so that the two cohorts can be analysed together across the adult age range.

Composition

Of 2,000 students who met the study physicians between October 2015 and June 2017, 1,870 were scanned. After one withdrawal, one scanner failure and 36 exclusions for incidental findings that needed medical referral, the described sample holds 1,832 participants: 1,320 women and 512 men, mean age 22.1 years (range 18.1 to 34.9). 1,722 were younger than 26. Participants were healthy volunteers; exclusion criteria were age over 35, pregnancy or nursing, claustrophobia and MRI contraindications.

Acquisition

All scans come from one Siemens Prisma 3 T scanner with a 64-channel head coil, acquired between November 2015 and November 2017 in sessions of about 45 minutes. Each session has a 3D MPRAGE T1w and a 3D SPACE FLAIR at 1 mm isotropic, an axial SWI (0.8 x 0.8 x 3.0 mm), multi-shell diffusion at 1.75 mm with b-values 300, 1000 and 2000 s/mm2, and a resting-state fMRI run of about 15 minutes (multiband 6, TR 850 ms, 2.4 mm). All 1,832 have T1w and FLAIR; SWI, diffusion and resting-state fMRI are available for 1,830, 1,823 and 1,814. T1w and FLAIR images are defaced with the UK Biobank face mask.

Annotations

No manual labels are described. The GIN processing platform (ABACI) produces image-derived phenotypes such as cortical thickness, surface area, tissue volumes, diffusion tensor and NODDI metrics, and resting-state connectivity. Global phenotypes for 1,831 participants are openly available as a table; the images are not.

Known limitations

• Not public. Access needs an approved i-Share collaboration proposal, a signed charter and a contribution to costs.
• About 72% of participants are women, which reflects the i-Share cohort, and almost all are under 26.
• Single site and single scanner, so it does not test generalisation across hardware.
• Cross-sectional: each participant was scanned once.