Striatal dopamine transporter and receptor availability correlate with relative cerebral blood flow measured with [ 11 C]PE2I, [ 18 F]FE-PE2I and [ 11 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 [ 11 C]PE2I (n = 20) and [ 18 F]FE-PE2I (n = 20) and the D2/3 tracer [ 11 C]raclopride (n = 18). Subjects with a [ 11 C]PE2I scan also underwent a dynamic scan with the serotonin transporter tracer [ 11 C]DASB. Binding potential (BP ND ) and relative tracer delivery (R 1 ) values were calculated on regional and voxel-level. Striatal R 1 and BP ND values were correlated, using either an MRI-based volume of interest (VOI) or an isocontour VOI based on the parametric BP ND image. An inter-tracer comparison between [ 11 C]PE2I BP ND and [ 11 C]DASB R 1 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 ND and R 1 for all three dopamine tracers. A similar correlation was found for the inter-tracer correlation between [ 11 C]PE2I BP ND and [ 11 C]DASB R 1 . 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.