Striatal dopamine transporter and receptor availability correlate with relative cerebral blood flow measured with [C]PE2I, [F]FE-PE2I and [C]raclopride PET in healthy individuals.

The aim of this retrospective study was to investigate relationships between relative cerebral blood flow and striatal dopamine transporter and dopamine D2/3 availability in healthy subjects. The data comprised dynamic PET scans with two dopamine transporter tracers [C]PE2I (n = 20) and [F]FE-PE2I (n = 20) and the D2/3 tracer [C]raclopride (n = 18). Subjects with a [C]PE2I scan also underwent a dynamic scan with the serotonin transporter tracer [C]DASB. Binding potential (BP) and relative tracer delivery (R) values were calculated on regional and voxel-level. Striatal R and BP values were correlated, using either an MRI-based volume of interest (VOI) or an isocontour VOI based on the parametric BP image. An inter-tracer comparison between [C]PE2I BP and [C]DASB R was done on a VOI-level and simulations were performed to investigate whether the constraints of the modeling could cause correlation of the parameters. A positive association was found between BP and R for all three dopamine tracers. A similar correlation was found for the inter-tracer correlation between [C]PE2I BP and [C]DASB R. Simulations showed that this relationship was not caused by cross-correlation between parameters in the kinetic model. In conclusion, these results suggest an association between resting-state striatal dopamine function and relative blood flow in healthy subjects.