PET-MRI of Reward System in Parkinson's Disease With RBD

"The PET-MRI will be performed using a Siemens Biograph mMR hybrid PET-MRI scanner. A 60-minute dynamic PET acquisition will begin following the intravenous injection of \\\[¹¹C\]raclopride (a radiotracer agonist of dopamine D2/D3 receptors) synthesized in the radiopharmaceutical laboratories of CERMEP. Simultaneously with the PET acquisition, brain MRI sequences will be acquired: 3D anatomical T1 and 3D T2, SWI, diffusion MRI (DTI), resting-state functional MRI, and arterial spin labeling (ASL) perfusion MRI.~Patients will undergo two PET-MRI scans on two consecutive days under two pharmacological conditions: Off and On dopamine:~* Day 1:\*\* The first PET-MRI session (TEPDopaOff) will be performed after a 12-hour withdrawal from usual dopaminergic treatment (Off dopamine).~* Day 2:\*\* The second PET-MRI session (TEPDopaOn) will be similar to the first, except it will take place 1 hour after administration of immediate-release Levodopa"