No Dopamine Agonist Modulation of Brain [ 18 F]FEOBV Binding in Parkinson's Disease.

The [ 18 F]fluoroethoxybenzovesamicol ([ 18 F]FEOBV) positron emission tomography (PET) ligand targets the vesicular acetylcholine transporter. Recent [ 18 F]FEOBV PET rodent studies suggest that regional brain [ 18 F]FEOBV binding may be modulated by dopamine D2-like receptor agents. We examined associations of regional brain [ 18 F]FEOBV PET binding in Parkinson's disease (PD) subjects without versus with dopamine D2-like receptor agonist drug treatment. PD subjects ( n = 108; 84 males, 24 females; mean age 68.0 ± 7.6 [SD] years), mean disease duration of 6.0 ± 4.0 years, and mean Movement Disorder Society-revised Unified PD Rating Scale III 35.5 ± 14.2 completed [ 18 F]FEOBV brain PET imaging. Thirty-eight subjects were taking dopamine D2-like agonists. Vesicular monoamine transporter type 2 [ 11 C]dihydrotetrabenazine (DTBZ) PET was available in a subset of 54 patients. Subjects on dopamine D2-like agonists were younger, had a longer duration of disease, and were taking a higher levodopa equivalent dose (LED) compared to subjects not taking dopamine agonists. A group comparison between subjects with versus without dopamine D2-like agonist use did not yield significant differences in cortical, striatal, thalamic, or cerebellar gray matter [ 18 F]FEOBV binding. Confounder analysis using age, duration of disease, LED, and striatal [ 11 C]DTBZ binding also failed to show significant regional [ 18 F]FEOBV binding differences between these two groups. Chronic D2-like dopamine agonist use in PD subjects is not associated with significant alterations of regional brain [ 18 F]FEOBV binding.