A PROSPECTIVE study has shown that elevated brain iron, measured using quantitative susceptibility mapping (QSM) MRI, may help predict the onset of mild cognitive impairment (MCI) and long-term cognitive decline in cognitively unimpaired older adults.
Brain iron accumulation has been identified as a potential marker for neurodegeneration, but its predictive value for early cognitive decline has remained uncertain. Researchers investigated how brain iron and amyloid-β (Aβ) levels, measured through QSM MRI and PET imaging, could predict MCI onset and cognitive decline.
The study, conducted between January 2015–November 2022, followed 158 cognitively unimpaired older adults (mean age: 69.5 years±8.1; 99 women) for up to 7.7 years. Of these, 110 also underwent amyloid PET imaging at baseline. Using Cox regression and linear mixed-effects models, the researchers explored the associations between tissue magnetic susceptibility, and time to MCI onset and cognitive scores.
Findings revealed that higher baseline susceptibility in the entorhinal cortex and putamen was associated with an increased risk of developing MCI in both the overall group and the PET group (entorhinal cortex, overall group versus PET subgroup: HR: 2.00; 95% CI: 1.23–3.23; P=0.005 versus HR: 3.59; 95% CI: 1.70–7.57; P<0.001, respectively). In the PET subgroup, higher susceptibility in the entorhinal cortex and putamen was linked to greater global cognitive decline, especially when combined with amyloid abnormality.
The authors concluded that increased tissue magnetic susceptibility in the entorhinal cortex and putamen is significantly associated with the onset of mild cognitive impairment and cognitive decline in cognitively unimpaired older adults, particularly in people with amyloid neuropathologic abnormalities.
Reference
Chen L et al. Susceptibility MRI helps predict mild cognitive impairment onset and cognitive decline in cognitively unimpaired older adults. Radiology. 2025;316(3):e250513.
