Quantification of total and nondisplaceable [18F]BF-227 binding. (a) Regions of interest, with (MSA+, in red) and without (MSA−, in white) aggregated alpha-synuclein staining were defined according to immunofluorescence ((A) MSA patient and (D) CTL subject). Corresponding total and nondisplaceable binding were extracted from MSA patients (B and C) and CTL subjects (E and F). (b) Computed displaceable [18F]BF-227 binding in MSA+, MSA−, and CTL regions of interest, plotted as individual points (for each MSA patient or CTL subject) and mean ± standard deviation. Differences between the three groups were not significant.