New MRI brain scan predicts Alzheimer's risk years before symptoms develop

Levels of iron in the brain could be a warning sign of future Alzheimer's disease, a new study suggests.

Researchers at Johns Hopkins University found that a special MRI technique called quantitative susceptibility mapping (QSM) can measure levels of brain iron.

"QSM can detect small differences in iron levels across different brain regions, providing a reliable and non-invasive way to map and quantify iron in patients, which is not possible with conventional MR approaches."  

This measurement could help predict the likelihood of mild cognitive impairment (MCI) and cognitive decline, even if the person has shown no symptoms.

After a follow-up period of 7½ years, the team concluded that higher iron levels in two key parts of the brain were linked to a higher risk of mild cognitive impairment, which is typically a precursor to the development of Alzheimer's dementia.

"And such brain iron changes may be measured years before memory loss, when the participants are still cognitively normal.

"Using QSM, we found higher brain iron in some memory-related regions that are linked to a higher risk of developing cognitive impairment and faster cognitive decline," Li said. "This risk is even higher when the participants have higher levels of amyloid pathologies."

The study did have some limitations, Li noted, including the smaller group of participants.

If larger, more diverse studies confirm these findings, it could support the use of this MRI technique for patients at a higher risk of dementia, the release stated.

The researchers also hope to make the QSM technology more standardized, faster and more widely accessible in clinical practice, he added.

"While iron chelation therapies (to remove iron) for Alzheimer's are currently explored, their effect is still not very clear and much more research is needed," he said.

The study was supported by the National Institute of Biomedical Imaging and Bioengineering, National Institute on Aging and the National Institutes of Health.