Increased susceptibility in the anterior hippocampal dentate gyrus and CA4 region of patients with mild cognitive impairment

Motivation: Iron abnormality in the hippocampal subregions may serve as an early biomarker complementary to amyloid-β deposition in Alzheimer's disease. Goal(s): To investigate magnetic susceptibility changes associated with iron deposition in hippocampal subregions of patients with mild cognitive impairment (MCI) using 7T quantitative susceptibility mapping (QSM). Approach: Manual hippocampal segmentations based on 7T QSM (isotropic 0.5 mm resolution) were performed on 13 MCI subjects and 13 normal controls. Hippocampal subregional susceptibility and inter-region contrast were compared between groups. Results: In patients with MCI, increased susceptibility in the anterior hippocampal dentate gyrus and CA4 leads to reduced susceptibility contrast within the hippocampus. Impact: Investigating iron accumulation in the hippocampal subregions with high spatial resolution using 7T holds promise for the early detection of abnormalities in Alzheimer's disease and for enhancing our understanding of the underlying pathological mechanisms.