P4‐540: CSF PTAU‐217 PERFORMS BETTER THAN PTAU‐181 IN DETECTING ABNORMAL RETENTION OF 18F‐FLORTAUCIPIR AND DISCRIMINATING ALZHEIMER'S DISEASE FROM OTHER NEURODEGENERATIVE DISORDERS. (1st July 2019) - Janelidze, Shorena; Smith, Ruben; Dage, Jeffrey; Proctor, Nicholas; Chai, Xiyun; Airey, David C.; Hansson, Oskar