Iron concentration linked to structural connectivity in the subthalamic nucleus: implications for deep brain...

Area of Science:

• Neuroimaging
• Neuroscience
• Medical Physics

Background:

• Parkinson's disease (PD) is a neurodegenerative disorder affecting motor control.
• Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for PD.
• Understanding the relationship between iron deposition and white matter tracts in the STN is crucial for optimizing DBS therapy.

Purpose of the Study:

• To investigate the correlation between iron concentration and white matter connectivity within the STN in PD patients.
• To explore the utility of quantitative susceptibility mapping (QSM) in assessing STN functional subdivisions.
• To determine if iron-QSM patterns can inform surgical planning for STN-DBS.

Main Methods:

• Preoperative 3T MRI including T1-weighted, diffusion tensor imaging (DTI), and quantitative susceptibility mapping (QSM) were acquired from nine PD patients.
• MR tractography was performed using the STN as seed region.
• Normalized QSM values were correlated with STN connectivity to predefined regions of interest.

Main Results:

• A significant negative correlation was observed between STN connectivity and QSM intensity for connections to the thalamus, premotor, motor, and sensory regions.
• Conversely, a significant positive correlation was found between STN connectivity and QSM intensity for connections to frontal, putamen, and brain stem areas.
• QSM effectively delineated STN borders and provided functional insights into its subdivisions.

Conclusions:

• Quantitative susceptibility mapping reveals distinct iron-to-connectivity patterns within the STN.
• These findings suggest that QSM can provide functional information about STN subdivisions.
• Iron-connectivity correlations may assist in personalized DBS surgical planning to mitigate potential side effects.