Ingenuity tf pet mr system

MR imaging was performed on a 3 Tesla Ingenuity TF PET-MR system (Philips Medical Systems, Best, The Netherlands) on the same day as the PET-CT acquisition. MRI analysis included 3D T1 (repetition time 7.9 ms, echo time 4.5 ms, flip angle 8°, measured voxel size 1 × 1 × 1 mm³) for region of interest (ROI) definition and 3D T2 Fluid Attenuated Inversion Recovery (FLAIR) (repetition time 4800 ms, echo time 279 ms, inversion time 1650 ms, measured voxel size 0.9 × 0.9 × 1.1 mm³) for lesion segmentation. In patients, additional post-contrast 2D T1 sequences (repetition time 600 ms, echo time 10 ms, measured voxel size 0.56 × 0.44 × 5 mm³) were acquired.

Three-dimensional T1-weighted MRI scans were acquired for all patients on a 3.0T Ingenuity TF PET/MR system (Philips Medical Systems, Best, The Netherlands) within a maximum of 2 and 6 months from [¹¹C]UCB-J and [¹⁸F]flortaucipir PET, respectively. None of the subjects had significant structural abnormalities that may have interfered with the analysis of the PET scans.

Imaging data were acquired and processed as described previously^{20 (link)}. Briefly, participants were asked to abstain from protein-containing breakfasts before a 4-hour [¹⁸F]DOPA scan (Ingenuity TF PET/MR system, Philips Healthcare, Cleveland, OH, USA) at rest. Carbidopa (150 mg in tablet form, a peripherally-acting DOPA decarboxylase inhibitor; Amerigen Pharmaceuticals, Lyndhurst, NJ, USA) was administered 60 min prior to intravenous [¹⁸F]DOPA injection to increase striatal activity and the signal-to-noise ratio^{21 (link)}. Striatal dopamine availability at steady state was calculated by estimating EDVR on a voxel-wise basis by graphical analysis, and averaging the value within the whole striatum. In exploratory analyses, striatal subregions (caudate nucleus, putamen and ventral striatum) were evaluated.