MAPT and Alzheimer disease: The radiotracer 18F-(2-(1-{6-{(2-[18F]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile) ([18F]FDDNP) was developed as a non-invasive biomarker to image NFTs and Aβ plaques in the brains of AD patients.35 An overview of tau studies using [18F]FDDNP can be found in Table 1.