AUTHOR=Kagerer Sonja M. , Vionnet Laetitia , van Bergen Jiri M. G. , Meyer Rafael , Gietl Anton F. , Pruessmann Klaas P. , Hock Christoph , Unschuld Paul G. 

TITLE=Hippocampal iron patterns in aging and mild cognitive impairment

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 17 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2025.1598859

DOI=10.3389/fnagi.2025.1598859

ISSN=1663-4365

ABSTRACT=IntroductionThe entorhinal cortex (EC)-hippocampus system is critical for memory and affected early in Alzheimer’s disease (AD). Cognitive dysfunction in AD is linked to neuropathological changes, including non-heme iron accumulation in vulnerable brain regions. This study characterized iron distribution in the EC-hippocampus system using ultra-high field (UHF) magnetic resonance imaging (MRI) at 7 Tesla (T) in aging and mild cognitive impairment (MCI), an AD at-risk state.Methods40 participants (mean age [SD] 69.2 [7.42] years; 12 mild cognitive impairment (MCI), 28 cognitively healthy controls (HC)) underwent UHF MRI at 7 T with turbo spin echo and quantitative susceptibility mapping (QSM). Gray matter segmentation was performed using FreeSurfer software. Intraclass correlation coefficients (ICCs) were calculated for hippocampal and EC measures.ResultsICCs for mean susceptibilities were 0.61 overall, 0.58 for HC, and 0.69 for MCI, with significant group differences between HC and MCI (Kolmogorov–Smirnov test, k = 0.625, p ≤ 0.05).DiscussionOur findings suggest a higher coherence of non-heme iron distribution in MCI. An increasingly uniform distribution of iron in MCI could reflect a clinical continuum ranging from healthy aging to pathologic brain change and cognitive disorder. This highlights the potential of non-heme iron as a biomarker for early AD co-pathology.