Different iron distribution patterns in Parkinson's disease and its motor subtypes: a quantitative susceptibility...

Area of Science:

• Neuroimaging
• Neurodegenerative Diseases
• Biomarkers

Background:

• Parkinson's disease (PD) is characterized by abnormal protein aggregation and neurodegeneration.
• Iron accumulation in specific brain regions is implicated in PD pathogenesis.
• Quantitative susceptibility mapping (QSM) offers a non-invasive method to assess iron deposition.

Purpose of the Study:

• To investigate iron deposition patterns in brain nuclei of PD patients using QSM.
• To determine if QSM-detectable iron patterns can distinguish between PD motor subtypes (PIGD and TD).
• To explore correlations between iron deposition and clinical severity in PD.

Main Methods:

• 34 PD patients and 30 healthy controls (HC) underwent brain MRI.
• 18 regions of interest were analyzed, including differentiation of globus pallidus (GP) into external (GPe) and internal (GPi) segments.
• QSM was used to quantify magnetic susceptibility, reflecting iron content.

Main Results:

• Significant differences in magnetic susceptibility were observed in the substantia nigra pars reticulate (SNr) and pars compacta (SNc) between PD and HC.
• QSM values in bilateral GPe, SNr, and SNc-R differed significantly between tremor dominance (TD) and postural instability and gait disorder (PIGD) subtypes.
• Iron deposition in the putamen (PUT) and SNc correlated with clinical severity scores (MDS-UPDRSIII, Hoehn-Yahr) in PD and its subtypes.

Conclusions:

• Pathologic iron deposition in PD brain nuclei is variable and influenced by age.
• Substantia nigra iron patterns show potential for differentiating PD motor subtypes.
• QSM may serve as a valuable tool for understanding PD heterogeneity and developing targeted therapies.