What funnels someone to me after their long and complicated journey is often an abnormality unseen or unfelt to them: an opacity on a chest X-ray.

Cytology screening only detects about three in four abnormalities.

With advancing technology, screening for fetal abnormalities has galloped ahead, and the test behind the new study become widespread about 10 years ago.

Celebrity Davina McCall's recent revelation that a colloid cyst in her brain was picked up on a routine screening has focused attention on how such scans can detect minor abnormalities.

The findings, which have been published by The Journal of Comparative Neurology, offer a compelling new explanation for commonly described brain pathologies observed in Alzheimer's disease, including amyloid-beta plaques, tau tangles, and spongiform abnormalities.