T807 tau tracer. Sagittal images from 80 to 100 minutes post-injection of a 56-year-old healthy subject (top left), mild cognitively impaired (MCI) subject (top right), mild Alzheimer’s disease (AD) subject with mini-mental state exam (MMSE) 21 (bottom left), and severe AD subject with MMSE 7 (bottom right). The intensity and extension of T807 uptake correlated to Braak and Braak stages of phosphorylated tau deposition, except in the area where severe neuronal degeneration is expected, for which the mild AD subject had the highest cortical retention. Reprinted from the Journal of Alzheimer's Disease, volume 34 (No 2) by Chien et al. Early Clinical PET Imaging Results with the Novel PHF-Tau Radioligand [F-18]-T807, p465, Copyright 2013, with permission from IOS Press .