Insight 46

Insight 46 is a neuroimaging sub-study of the MRC National Survey of Health and Development (NSHD), the cohort born in England, Scotland and Wales in one week of March 1946. Because all participants are almost the same age and have decades of earlier health, cognitive and social data, it is used to study preclinical Alzheimer's disease, cerebrovascular disease and brain ageing in the general population. The MRC Unit for Lifelong Health and Ageing at UCL manages data access.

Composition

Phase 1 (2015 to 2018) enrolled 502 cohort members (256 male, 246 female), drawn at random from those who had attended the age 60 to 64 clinic and had the required life course data. Median age at the first visit was 70.7 years (range 69.2 to 71.8). 471 completed the PET/MRI scan. Phase 2, about two years later, scanned 369, and 367 have PET and MRI from both phases. Phase 3 started in 2021, opened recruitment to other cohort members and is expected to finish in 2026; by June 2023 it had 111 amyloid and 109 tau PET/MRI scans.

Acquisition

All PET/MRI in phases 1 and 2 used one Siemens Biograph mMR 3 T PET/MR at University College London Hospitals. The protocol has 3D T1-weighted MPRAGE, 3D T2 and 3D FLAIR at 1.1 mm isotropic, resting-state fMRI, multi-shell diffusion, pseudo-continuous ASL and a three-echo 3D gradient echo (0.86 x 0.86 x 1.5 mm) from which T2*-weighted images, T2* maps, SWI and quantitative susceptibility maps are made. Amyloid PET used florbetapir in phases 1 and 2. Phase 3 uses florbetaben for amyloid and MK-6240 for tau, and adds MP2RAGE, multi-delay ASL and IVIM on a separate 3 T Siemens Prisma.

Annotations

No manual image labels are published. The protocol describes visual amyloid PET reads, SUVR, automated brain and hippocampal segmentation, and visual rating plus automated quantification of white matter hyperintensities and microbleeds. The NSHD website lists derived variables such as amyloid status, brain volumes and white matter hyperintensity volume.

Known limitations

• The NSHD enrolled only white singleton births from 1946, so other ages and ethnic groups are not covered.
• Participants were more educated and of higher socioeconomic position than the cohort members not recruited, and had to be fit to travel to London.
• The data are offered through the NSHD variable request process. Whether raw images can be requested is not stated publicly.