Fig. 6.

DAT availability in the putamen versus the substantia nigra. The relationship between the mean DAT availability in the putamen (left and right side averaged) and the SN (left and right side averaged), measured with FE-PE2I in HC and patients. Empty squares indicate HC that are not yet followed up. Filled squares indicate HC that are still healthy at follow-up after 2 years. Filled circles indicate patients that fulfilled clinical criteria for PS at inclusion and fulfilled clinical criteria for a specific parkinsonian syndrome at follow-up after 2 years. Empty circles indicate patients that fulfilled clinical criteria for PS at inclusion, not yet clinically followed up. Filled triangles indicate patients that fulfilled clinical criteria for PS at inclusion, but did not fulfil clinical criteria for a specific parkinsonian syndrome at follow-up after 2 years. HC, healthy controls; PS, parkinsonian syndrome; SN, substantia nigra; BP_ND, binding potential relative to non-displaceable binding; FE-PE2I, [¹⁸F]FE-PE2I PET; FP-CIT, [¹²³I]FP-CIT SPECT