Six‐month follow‐up of ARIA‐H and iron deposition in real‐world lecanemab therapy for Alzheimer's disease: Evidence from a Chinese 7T MRI cohort

Using 7T magnetic resonance imaging (MRI), this study for the first time visualized amyloid-related imaging abnormality with hemorrhages/hemosiderin deposition (ARIA-H) at a submillimeter resolution, characterized by aggregated, clustered cerebral microbleeds in a perivascular distribution, suggesting overlapping pathology with cerebral amyloid angiopathy. The susceptibility-weighted imaging sequence on 7T MRI enabled detection of ARIA-H up to 4 months earlier. Plasma amyloid beta 42 (Aβ42) and tau phosphorylated at threonine 217 (p-tau 217) levels are sensitive biomarkers for amyloid targeted therapy. Quantitative susceptibility mapping (QSM) analysis demonstrated reduced cortical iron burden post-treatment, which has significant associations with plasma Aβ42 and p-tau 217 levels, highlighting QSM-derived iron quantification as a promising neuroimaging indicator for amyloid-targeted therapeutics.