MAPT and Alzheimer disease: Results from the different studies have consistently shown an excellent signal-to-noise ratio of each of these three tracers for imaging brain tau deposition in AD with a several fold higher in vivo retention in target regions consistent with neuropathological neurofibrillary tau staging in AD patients compared to cognitively unimpaired individuals [3, 4, 6, 15, 19, 34, 41, 42].