The density of the dopamine transporter (DAT) continues to decline in the striatum of Parkinson’s disease (PD) patients, while they get at risk for developing levodopa-induced dyskinesias (LIDs). Here, we studied the role of DAT-specific imaging as a prognostic marker of dyskinesias.Methods
We retrospectively selected 42 PD patients who had SPECT imaging with 123I-Ioflupane approximately five years ago during the diagnosis of PD. 15 patients of them were rescanned with 123I-Ioflupane SPECT after 6.3±3.0 years. We divided the PD patients according to the presence or absence of dyskinesias. SPECT data were analysed for the putamen by a semi-quantification approach.Results
10 PD patients had developed LIDs, while 32 were non-dyskinetic. The putaminal mean 123I-Ioflupane uptake in the LIDs (1.7±0.4) group was not statistically different as compared to the non-LIDs group (1.7±0.5;p>010). All 15 PD patients who had a second SPECT scan showed significant reductions in the putaminal 123I-Iofluplane uptake (p<0.001) as compared to their first scan. Within this subgroup, the LIDs (n=8) had significantly lower DAT uptake (1.1±0.3) as compared to the non-LIDs patients (n=7); (1.5±0.5; p<0.05).Conclusion
123I-Ioflupane SPECT imaging in de novo PD, cannot predict the onset of LIDs within five years from diagnosis. As shown in the group that repeated 123I-Ioflupane SPECT imaging, the onset of LIDs may be linked to a faster decline of putaminal DAT availability.