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

Abstract

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 18F-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 (Aj3)-stable (n = 67), Aj3-progressor (n =18), Aj3+ stable (n = 33), or Aj3+ 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 E4 carrier status, global cortical SUVR, and clinical follow-up duration. RESULTS: Aj3-MCI progressors showed higher |AI| in the lateral orbitofrontal cortex (790 vertices, cluster-wise p = 0.0002). Aj3+ 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.