Figure 2.

PET imaging at baseline. A, Spatially normalized mean parametric images of each radiotracer collected at baseline superimposed on the brain Macaca fascicularis MRI template (Ballanger et al., 2013). The parametric images are shown in color, whereas the MRIs are shown in grayscale. Colors represent the level of binding expressed as uptake ratio using the cerebellum as a nonspecific reference for each radioligand (K_i for [¹⁸F]DOPA and BP_ND for [¹¹C]raclopride, [¹¹C]DASB, and [¹⁸F]MPPF). Red represents high K_i or BP_ND, whereas blue denotes low K_i or BP_ND. For each radiotracer, three coronal (first three rows), one sagittal (fourth row), and one transaxial (fifth row) slices are shown. B, Negative correlation reported within the pallidum internal (GPi) and external (GPe) parts between both the [¹¹C]Raclopride and [¹¹C]DASB BP_ND collected at baseline and the maximal parkinsonian score obtained in the full symptomatic state (n = 5).