Category: Parkinson's disease: Neuroimaging
Objective: To investigate the spatial relationship between striatal dopaminergic denervation and nigral iron accumulation in Parkinson’s disease (PD) using functional subregional parcellation.
Background: Excessive nigral iron deposition is implicated in PD pathogenesis, yet its mechanistic link to dopaminergic terminal dysfunction remains unclear due to inconsistent correlations from conventional whole-structure analyses. Given the heterogeneous progression of neurodegeneration, a topography-based approach may clarify this relationship.
Method: Twenty-two patients with early-to-moderate stage PD underwent both ¹⁸F-FP-DTBZ-PET/CT for vesicular monoamine transporter type 2 (VMAT2) imaging and quantitative susceptibility mapping (QSM) at 3T MRI. Two groups of healthy control (HC-PET, n=18; HC-QSM, n=22) were scanned with VMAT2-PET or QSM. The striatum and substantia nigra (SN) were manually parcellated into sensorimotor, associative, and limbic subregions. Regional QSM values and DTBZ standard uptake value ratios (SUVRs) were compared, and correlations were analyzed.
Results: PD patients showed significantly reduced VMAT2 binding in all striatal subregions (all p≤0.05) but selectively elevated iron deposit only in the limbic SN (p=0.023). Inverse correlations emerged between contralateral limbic striatal SUVR and limbic SN susceptibility (r=-0.444, p=0.038). Notably, limbic striatal denervation correlated with sensorimotor SN iron (r=-0.589, p=0.004), and associative striatal denervation correlated with both limbic and sensorimotor SN iron (r=-0.544, p=0.009; r=-0.619, p=0.002), which persisted after adjustment.
Conclusion: Dopaminergic denervation and nigral iron accumulation exhibit topographic specificity, with limbic/associative striatal dysfunction linked to iron overload in remote sensorimotor SN subregions. These findings support circuit-level vulnerability beyond direct projections, consistent with the spiral model of striato-nigral connectivity. Functional subregional analysis provides a refined framework for elucidating PD pathophysiology.
To cite this abstract in AMA style:
YJ. Duan, XL. Liu, XJ. Dan, Y. Li, H. Zhang, HW. Qiao, W. Mao, EH. Xu, SY. Liu, P. Chan. Topographic Heterogeneity of Dopaminergic Denervation and Iron Deposition in Functional Subregions of Nigrostriatal System in Parkinson’s Disease [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/topographic-heterogeneity-of-dopaminergic-denervation-and-iron-deposition-in-functional-subregions-of-nigrostriatal-system-in-parkinsons-disease/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/topographic-heterogeneity-of-dopaminergic-denervation-and-iron-deposition-in-functional-subregions-of-nigrostriatal-system-in-parkinsons-disease/