Quantitative Susceptibility Mapping in Parkinson's Disease.

Area of Science:

• Neuroimaging
• Medical Physics
• Neurology

Background:

• Iron deposition in the substantia nigra is linked to Parkinson's disease (PD) using Quantitative Susceptibility Mapping (QSM) and R2* mapping.
• Previous studies show conflicting findings in other deep gray matter nuclei and limited investigation into QSM/R2* sensitivity for morphological changes and clinical correlations.

Purpose of the Study:

• To investigate the sensitivity of QSM and R2* mapping for detecting morphological changes in subcortical deep gray matter nuclei in PD.
• To explore the relationship between QSM/R2* findings and clinical measures of PD severity.

Main Methods:

• Quantitative MRI at 3T was performed on 66 PD patients and 58 controls.
• Susceptibility and R2* maps were reconstructed using a spoiled multi-echo 3D gradient echo sequence.
• Mean susceptibilities and R2* rates were measured in subcortical deep gray matter nuclei and correlated with clinical variables.

Main Results:

• PD patients showed increased R2* in the substantia nigra compared to controls.
• QSM revealed higher magnetic susceptibilities in PD patients in the substantia nigra, nucleus ruber, thalamus, and globus pallidus.
• Magnetic susceptibility in several regions correlated with levodopa-equivalent daily dose (LEDD) and clinical markers (MDS-UPDRS), and Hoehn & Yahr scale scores.

Conclusions:

• QSM demonstrated superior sensitivity for PD-related tissue changes in nigrostriatal pathways compared to R2*.
• QSM findings correlated with levodopa dosage and disease severity, suggesting widespread pathology.
• QSM represents a novel, highly sensitive MRI technique for investigating PD.