In Vivo PET of Synaptic Density in Cognitive Disorders

Forty healthy controls will be included as well as 110 patients that were referred by the UZ Leuven memory clinic with uncertain diagnosis of cognitive impairment and are already sent for \[18F\]-FDG PET imaging in their workup (estimated subgroup size: 30 patients with final diagnosis AD (aMCI); 20 patients with DLB; 30 patients with FTD; 30 patients with late-life psychiatric disorder). Scans will be acquired on a 3T GE Signa PET-MR scanner, for 90 minutes starting at injection of 150 MBq \[18F\]-SynVesT-1 for healthy controls, and from 60 to 90 minutes post injection of 150 MBq \[18F\]-SynVesT-1 for patients. For healthy controls, discrete arterial blood samples will be manually collected every 10s from 10 to 90s; every 15s from 90s to 3min; and then at 3.5, 5, 6.5, 8, 12, 15, 20, 25, 30, 45, 60, 75 and 90min. Plasma samples for correction of radiometabolites will be collected at 3, 8, 15, 30, 60 and 90min after injection. All healthy controls will also be subjected to a neuropsychological test battery and if necessary, additional limited neuropsychological testing on top of those from the memory clinic will be carried out in patients.