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Progression of White Matter Degeneration in Early Parkinson's Disease: A Multicenter Evaluation Using Diffusion Tensor Imaging

Zhang, Y; Wu, K; Schuff, N; The Parkinson\'s Progression Markers Initiative
AD/PD: Nice, France
Download Presentation: Zhang-AD.PD-2015.pdf
OBJECTIVES: This study aimed to identify the utility of MRI diffusion tensor imaging (DTI) in measuring abnormal white matter (WM) progression in patients enrolled in the Parkinson's progression marker initiative (PPMI). PPMI is an international, multicenter, longitudinal study assessing biochemical, clinical, and imaging biomarkers of Parkinson's disease (PD) progression.

METHODS: 48 healthy controls (age=59.9±11) and 110 de-novo PD patients (age=60.3±9) had MRI-DTI scans at baseline and follow-up over 12.6±1 months. Image processing included an intra-subject registration of all time points and an inter-subjects registration to a brain atlas using DARTEL. Fractional anisotropy (FA) and WM probabilistic index were measured in 108 WM and 18 basal ganglia ROIs of each subject at each time point. Linear mixed-effect models between-group within-subject analyses were conducted to examine group differences in rates of FA.

RESULTS: The Figure indicates regional pattern of significantly increased annual rates of FA reduction (FDR-adjusted p<0.05) in patients compared to controls. PD was associated with greater rates of FA reduction predominantly in the basal ganglia and the medial temproparietal regions, without significant differences between ipsilateral and contralateral hemispheres (corresponding to the body side of symptom at onset). Among these regions, substantia nigra yielded the highest rate of FA reduction (contralateral=3.8%/year, ipsilateral=3.7%/year) from baseline.

CONCLUSIONS: The results suggest that increased rates of WM degeneration are a potential marker of PD progression.