Researchers at Johns Hopkins University found that a special MRI technique called quantitative susceptibility mapping (QSM) can measure levels of brain iron. "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." Also, besides serving as a biomarker, brain iron may become a future therapeutic target."