Dopamine transporter binding in patients with juvenile myoclonic epilepsy using [11C]PE2I and PET

Objectives Juvenile myoclonic epilepsy (JME) is frequently associated with behavioral disturbance and problems with social integration, which may be caused by frontal lobe and subcortical abnormalities. We tested whether JME can be associated with changes in the dopamine transmission system in the basal ganglia using [11C]PE2I and PET. In the previous studies, we had findings in the midbrain, but not in the basal ganglia.

Methods [11C]PE2I and PET studies were performed on eight patients with JME and seven normal control subjects. All patients were treated with sodium valproate. The dopamine transporter binding was estimated in the basal ganglia and cerebellum using the kinetic analysis with metabolite corrected arterial input and reference tissue models such as the simplified reference tissue model (SRTM) and non-invasive linear graphical analysis (DVR). The cerebellum was used as the reference region.

Results In comparison with binding parameters in the striatum of normal control subjects, there was no significant difference in BP values obtained by the reference tissue models. However, a significant increase of k3/k4 (binding potential) obtained by the kinetic analysis was observed in patients with JME (p<0.01), and there was no significant difference of k5/k6 in the cerebellum.

Conclusions Dopamine transmission may be altered in the dopaminergic neurons, and related to interictal dysfunction in JME. Although the kinetic analysis using metabolite corrected arterial input is preferable, the reference tissue models are also useful, but we should carefully assess the binding parameter values