Objective: Dyskinesia is the most common motor complication in advanced Parkinson’s
Disease (PD) and has a severe impact on daily life. But the mechanism of dyskinesia is still poorly
understood. This study aims to explore risk factors for disabling dyskinesia in PD and further analyze
the Vesicular Monoamine Transporter 2 (VMAT2) distribution (labeled with 18F-AV133) in
the corpus striatum and the 18F-fluorodeoxyglucose (18F-FDG) metabolism of different brain regions
Methods: This is a cross-sectional study involving 135 PD patients. They were divided into disabling
dyskinesia group (DD group, N=22) and non-dyskinesia group (ND group, N=113). All the
patients were agreed to undergo PET-CT scans. Clinical data were analyzed between two groups
by using multivariate logistic regression analysis, and risk factors for disabling dyskinesia were
then determined. The standard uptake value ratios (SUVr) of 18F-AV133 in the corpus striatum and
the 18F-FDG metabolism of different brain regions were identified and calculated by the software.
Results: 16.3% patients have disabling dyskinesia. DD group were more likely to have longer Disease
Duration, higher Hoehn-Yahr degree, more severe clinic symptoms, more frequent sleep behavior
disorder, and higher levodopa dose equivalency than ND group (P < 0.05). After adjusting
confounding factors by multivariate logistic regression, DD group had longer PD duration and
high levodopa dose equivalency compared with ND group (P < 0.05). There is no significant difference
between the VMAT2 distribution (labeled with 18F- AV133) in the putamen and caudate
between two groups. And the 18F-FDG metabolic changes in cortical and subcortical regions did
not show a significant difference between the two groups either (P > 0.05).
Conclusion: Long PD duration and high levodopa dose equivalency were two independent risk
factors for disabling dyskinesia in PD patients. Compared to non-dyskinesia PD patients, there was
no significant dopamine decline of the nigrostriatal system in disabling dyskinesia PD patients.
Activities of different brain regions were not different between the two groups by 18F-FDG PETCT.