18F-THK5351 Uptake May Not Estimate Neurofibrillary Tangles in In Vivo Images

Currently, monoamine oxidase B is recognized as the primary target of 18 F-THK5351, although 18 F-THK5351 was initially developed to target neurofibrillary tangles (NFTs) in Alzheimer disease. When clinically applying 18 F-THK5351 PET to visualize ongoing astrogliosis via estimating monoamine oxidase B levels, a crucial concern is how much degree 18 F-THK5351 uptake reflects NFTs in in vivo images. To unravel this concern, a head-to-head comparison between 18 F-THK5351 and 18 F-MK-6240 (estimating NFT) images in the NFT lesion ideally without accompanying astrogliosis is essential. Here, we present such a case suggesting that 18 F-THK5351 uptake may not estimate NFTs in in vivo images.