Objective: This study was designed to explore in Parkinson’s disease (PD) the role of dopamine transporter (DAT)-specific single photon emission computed tomography (SPECT) imaging as a prognostic marker of levodopa–induced dyskinesias (LIDs).

Background: As PD progresses, the density of the DAT in the striatal dopaminergic terminals continues to decline, while patients with PD are at risk for developing LIDs.

Methods: We retrospectively selected 42 PD patients who underwent SPECT imaging with 123I-Ioflupane (DAT-specific in vivo marker) approximately five years ago during the diagnosis of PD.

15 patients of the 42, were rescanned with 123I-Ioflupane SPECT 6.3±3.0 years after their first scan. 

We divided the PD patients according to the presence or absence of dyskinesias as LIDs and non-LIDs. SPECT data were analysed for the putamen by a semi-quantification approach using the occipital cortex as a reference.

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 had significant reductions in the putaminal 123I-Iofluplane uptake (p<0.001) as compared to the first scan. Within the group of 15, the LIDs (N=8) had significantly lower DAT uptake (1.1±0.3) as compared to the non-LIDs group (N=7); (1.5±0.5; p<0.05).

Conclusions: 123I-Ioflupane SPECT imaging in de novo PD, cannot predict the onset of LIDs within five years from diagnosis. As shown in the subgroup that repeated 123I-Ioflupane SPECT imaging, an onset of LIDs may be linked to a faster decline of putaminal DAT availability.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/spect-imaging-of-striatal-dat-availability-in-parkinsons-changes-over-time-and-relevance-to-dyskinesias/