Fig. 1

Dendrograms of the clustering solutions for the [¹⁸F]Florbetaben standardized uptake value ratios of each of the 20 regions of interest for the A Parkinson’s disease patient group on the left and the B healthy control group on the right. The blue line shows the cut-off solution with three clusters. The three clusters are colour coded in orange for cluster 1 (C1), purple for cluster 2 (C2), and red for cluster 3 (C3)