A new study found that dopamine transporter imaging may help monitor Parkinson’s disease progression by tracking motor symptom worsening over time.
Investigators analyzed data from 719 patients with Parkinson’s disease (PD) who were followed for up to 5 years as part of the Parkinson’s Progression Markers Initiative. They evaluated 1,981 imaging and clinical data points, with motor symptoms measured using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale motor part III (MDS-UPDRS-III).
The investigators showed that a decline in dopamine transporter (DaT) signal in the less affected putamen was associated with worsening motor function on the opposite side of the body. This link remained consistent whether tremor symptoms were included or excluded from the analysis (beta = –0.07, P = .002 without tremor; beta = –0.08, P = .003 with tremor).
“Our findings support the use of repetitive DaT imaging for objectively monitoring PD progression. This could facilitate personalized disease tracking, subtyping, and intervention testing in the future,” said lead study author Verena Dzialas, MSc, of the Department of Nuclear Medicine in the Faculty of Medicine and University Hospital Cologne at the University of Cologne in Germany, and colleagues.
No statistically significant relationship was observed between motor worsening and DaT signal decline in the more affected putamen or the caudate nuclei.
The participants had a mean age of 62.2 ± 9.5 years at baseline, and 62% of them were male. The mean disease duration at study start was 12.5 ± 17.8 months, and follow-up imaging and assessments occurred over an average of 31.7 months.
The investigators controlled for covariates, including age, sex, education, handedness, cognitive function, antidepressant use, and levodopa equivalent daily dose (LEDD). Higher age and longer disease duration were associated with more severe motor symptoms, whereas sex and antidepressant use were not significantly related to progression.
The patients showed an average annual increase of approximately 2.4 points on the MDS-UPDRS-III. The mean specific binding ratio (SBR) for the less affected putamen declined from 1.0 ± 0.37 at baseline to 0.65 ± 0.28 by year 4.
Although the association between DaT decline and motor progression was statistically significant, the investigators noted that the effect size was small, likely reflecting the slow clinical and imaging changes typical of PD progression.
The study was among the first large, longitudinal analyses to establish a link between regional DaT imaging changes and motor symptom worsening in PD. According to the investigators, future research could refine how DaT imaging is used to guide personalized monitoring and treatment strategies.
Full disclosures are available in the original publication.
Source: Annals of Neurology