Regional amyloid PET asymmetry and long‐term clinical trajectory in mild cognitive impairment

INTRODUCTION Hemispheric amyloid positron emission tomography (PET) asymmetry may capture prognostic information beyond binary amyloid status in amnestic mild cognitive impairment (aMCI). METHODS We retrospectively studied 158 aMCI patients with baseline 18 F‐florbetaben PET and magnetic resonance imaging acquired within 12 months and a mean follow‐up of 6.89 ± 2.63 years. Participants were classified as amyloid beta (Aβ)− stable ( n = 67), Aβ− progressor ( n = 18), Aβ+ stable ( n = 33), or Aβ+ progressor ( n = 40). Vertex‐wise cortical standardized uptake value ratio (SUVR) asymmetry (|AI|) was analyzed using surface‐based general linear models adjusted for age, sex, education years, apolipoprotein E ε4 carrier status, global cortical SUVR, and clinical follow‐up duration. RESULTS Aβ− MCI progressors showed higher |AI| in the lateral orbitofrontal cortex (790 vertices, cluster‐wise p = 0.0002). Aβ+ MCI progressors showed lower |AI| in the lingual gyrus (478 vertices, cluster‐wise p = 0.0001). No cross‐status contrast yielded a significant cluster in the covariate‐adjusted model. DISCUSSION Amyloid PET asymmetry reflects prognostic heterogeneity in aMCI, with distinct distributional patterns according to amyloid status.