Regional homogeneity differences in resting-state fMRI between Parkinson’s disease and multiple system atrophy-parkinsonian type

Both Parkinson's disease (PD) and the Multiple system atrophy-parkinsonian type (MSA-P) belong to the category of α-synucleinopathies, characterized by overlapping clinical manifestations and a high risk of misdiagnosis. The aim of this study is to provide objective imaging biomarkers for differentiating PD from MSA-P. We enrolled 25 patients with PD, 15 patients with MSA-P, and 20 healthy controls (HC). Resting-state functional magnetic resonance imaging (rs-fMRI) was employed to analyze regional homogeneity (ReHo) differences between PD and MSA-P groups. The discriminative capacity of ReHo values in these differential brain regions for distinguishing PD from MSA-P was subsequently evaluated. Compared to MSA-P, PD showed decreased ReHo in cerebellar lobule IX, left fusiform gyrus, and right thalamus, but increased ReHo in the right cuneus. In PD, ReHo in cerebellar lobule IX, left fusiform gyrus negatively correlated with UPDRS-III scores (r=- 0.8548, P< 0.001), while right cuneus ReHo positively correlated (r=0.6526, P=0.0004). The ReHo values in cerebellar lobule IX, left fusiform gyrus showed optimal discriminative power between PD and MSA-P groups, achieving an area under the curve (AUC) of 0.8693 (P< 0.001). Our study enhances understanding of altered neural synchronization in specific brain regions under rs-fMRI in PD and MSA-P. We established the link between ReHo changes in localized areas and PD clinical manifestations. Notably, ReHo alterations in cerebellar lobules IX and fusiform gyrus serve as potential biomarkers for differentiating PD from MSA-P.