UK Biobank data is openly available to researchers including non-imaging experts. However, imaging data is considerably more complex than most of the existing UK Biobank measures. Extensive post-processing is required to align images across subjects and remove artefacts. Moreover, information is usually encoded across multiple voxels, requiring further processing to extract relevant features. Even with carefully-prepared IDPs, meaningful interpretation requires care because MRI is generally an indirect measure of the biology of interest. Apparent structural atrophy can be susceptible to misinterpretation39; functional MRI signals can reflect vascular properties rather than neural activity40; and diffusion MRI is sensitive to many aspects of tissue microstructure14. A final challenge is that data sizes have become extremely large, requiring “big data” techniques; the brain imaging data in UK Biobank will ultimately surpass 0.2PB even without data inflation during post-processing.
