PET measurement of longitudinal amyloid load identifies the earliest stages of amyloid-beta accumulation during Alzheimer's disease progression in Down syndrome. - Matthew D. Zammit; Dana L. Tudorascu; Charles M. Laymon; Sigan L. Hartley; Shahid H. Zaman; Beau M. Ances; Sterling C. Johnson; Charles K. Stone; Chester A. Mathis; William E. Klunk; Ann D. Cohen; Benjamin L. Handen; et al. (NeuroImage, 2021)