Objective: This study aimed to identify regions with altered brain iron accumulation using quantitative susceptibility mapping (QSM) and to investigate the association between iron deposition and dopaminergic deficits in Parkinson’s disease (PD).

Background: Iron overload is common in neurodegenerative diseases, including Parkinson’s Disease (PD). QSM enables in vivo assessment of brain iron distribution, but the spatial pattern of iron accumulation across the brain and its relationship with striatal dopaminergic dysfunction in PD remain incompletely understood.

Method: A total of 76 right-handed PD patients and 32 age-, and sex-matched healthy controls (HC) were included. All PD patients additionally received 11C-CFT PET scanning to assess dopamine transporter (DAT) availability, reflecting striatal dopaminergic deficits. The QSM and CFT images were co-registered to T1-weighted images and normalized into standard space through FSL. Regional QSM values were extracted using the Anatomical Automatic Labelling 3 (AAL3) atlas. DAT standardized uptake value ratios (SUVRs) were calculated for the caudate nucleus (CAU), anterior putamen (aPUT), and posterior putamen (pPUT), using the occipital cortex as the reference region. Independent t-tests were used to identify regions with increased iron accumulation in PD. Partial correlation analysis was performed to explore associations between regional QSM values and mean bilateral DAT SUVRs in the CAU, aPUT, and pPUT. Grey matter volume (GMV, derived from FreeSurfer) was also included as a covariate to control for atrophy.

Results: Compared with HC, PD patients exhibited significantly increased iron accumulation in 37 brain regions (p < 0.05), of which 28 were bilaterally symmetric regions, including the supplementary motor area, basal ganglia nuclei, and the substantia nigra (SN). After adjusting for age, sex, and GMV, the QSM value of the left SN pars compacta (SNpc) was negatively correlated with the mean DAT SUVRs of bilateral CAU (r=-0.322, p=0.005), aPUT (r=-0.242, p=0.038), and pPUT (r=-0.238, p=0.042).

Conclusion: Widespread iron overload was observed in PD. Among these regions, the QSM value of SNpc may serve as a potential imaging biomarker of striatal dopaminergic deficits in PD.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/quantitative-susceptibility-mapping-revealed-regional-iron-alteration-and-as-a-biomarker-for-dopaminergic-deficits-in-parkinsons-disease/