ObjectiveWe wished to explore Parkinson's disease subtypes by clustering analysis based on the multimodal magnetic resonance imaging indices amplitude of low-frequency fluctuation and gray matter volume. Then, we analyzed the differences between PD subtypes.MethodsEighty-six PD patients and 44 healthy controls were recruited. We extracted ALFF and GMV according to the Anatomical Automatic Labeling partition using Data Processing and Analysis for Brain Imaging software. The Ward linkage method was used for hierarchical clustering analysis. DPABI was employed to compare differences in ALFF (...) and GMV between groups.ResultsTwo subtypes of PD were identified. The “diffuse malignant subtype” was characterized by reduced ALFF in the visual-related cortex and extensive reduction of GMV with severe impairment in motor function and cognitive function. The “mild subtype” was characterized by increased ALFF in the frontal lobe, temporal lobe, and sensorimotor cortex, and a slight decrease in GMV with mild impairment of motor function and cognitive function.ConclusionHierarchical clustering analysis based on multimodal MRI indices could be employed to identify two PD subtypes. These two PD subtypes showed different neurodegenerative patterns upon imaging. (shrink)

ObjectiveThis study aimed to investigate the morphometric alterations in the cortical and subcortical structures in multiple system atrophy patients with mild cognitive impairment, and to explore the association with cognitive deficits.MethodsA total of 45 MSA patients and 29 healthy controls were recruited. FreeSurfer software was used to analyze cortical thickness, and voxel-based morphometry was used to analyze the gray matter volumes. Cortical thickness and gray matter volume changes were correlated with cognitive scores.ResultsCompared to healthy controls, both MSA subgroups exhibited widespread (...) morphology alterations of brain structures in the fronto-temporal regions. Direct comparison of MSA-MCI and MSA-only patients showed volume reduction in the left superior and middle temporal gyrus, while cortical thinning was found in the left middle and inferior temporal gyrus in MSA-MCI patients. Cortical thinning in the left middle temporal gyrus correlated with cognitive assessment and disease duration.ConclusionStructural changes in the brain occur in MSA-MCI patients. The alteration of brain structure in the left temporal regions might be a biomarker of cognitive decline in MSA-MCI patients. (shrink)