Hr camera

All data (MEG, PET and MRI) were collected from the same participants at the CERMEP imaging centre (Lyon, France). The MEG data were recorded in a magnetically shielded room using a 275-channel CTF whole-head system. The signals were band-pass filtered at 0.016-150 Hz and sampled at 600 Hz. The PET data were recorded with a Siemens HR + camera, and ^[11C]flumazenil (FMZ), an agent that binds to benzodiazepine (BZD) receptor, was used. FMZ (RO15-1788) was labeled with 11C, using the methylation process50 (link). A dynamic 3D acquisition was applied providing 12 consecutive frames of 63 contiguous 2.42 mm thick slices, with an isotropic spatial resolution near 5 mm³ FWHM (full width at half-maximum). A 68Ge transmission scan was used to measure the attenuation correction. A partial saturation protocol consisting of a single intravenous injection of a mixture of 5 mCi of ^[11C]FMZ and 0.01 mg/kg of unlabeled FMZ was used, followed by acquisition of the emission data for 55 minutes. This single injection allowed the calculation of B′max parametric images, i.e., estimates of receptor density, without arterial blood sampling51 (link). Anatomical MRIs were collected with a 1.5 Tesla scanner (Siemens Sonata Maestro Class).

All subjects underwent brain MRI, ¹⁸F-FDOPA PET and vesicular acetylcholine transporter (VAChT) PET imaging with ¹⁸F-FEOBV. MRI of Parkinson’s disease subjects was acquired using Siemens Magnetom Prisma 3 T MRI scanners, equipped with SENSE-8 channel head coil. For each subject, anatomical T₁-weighted images were obtained using a sagittal 3D gradient-echo T₁-weighted sequence with 0.9 × 0.9 × 0.9 mm acquisition. Control subjects underwent a T₁-weighted MRI scan (3 T Intera) with 1.0 × 1.0 × 1.0 mm acquisition. ¹⁸F-FEOBV imaging was performed on the same day as MRI. For ¹⁸F-FEOBV PET imaging, participants first underwent lose-dose CT for attenuation and scatter correction using either a Biograph 40-mCT or 64-mCT (Siemens Healthcare). Both scanners were EARL certified, had the same software version and used identical acquisition and reconstruction protocols and PET detectors. Thirty-minute scans (in six 5-min frames) were acquired at 210 min post-bolus injection of ¹⁸F-FEOBV. ¹⁸F-FDOPA PET was performed after at least 6 h of fasting (4 h for diabetic patients). Participants were premedicated with carbidopa 60 min before receiving 200MBq of the FDOPA tracer, 90 min after which the PET-scan was formed on a Siemens HR+ camera.