Assessing Mild Cognitive Impairment in Parkinson's Disease by Magnetic Resonance Quantitative Susceptibility Mapping Combined Voxel-Wise and Radiomic Analysis

Background: The relationship between iron accumulation in the central nervous system and cognitive decline in Parkinson's disease (PD) has not been fully elucidated. This study aimed to explore the value of quantitative susceptibility mapping in assessment of mild cognitive impairment (MCI) in PD. Methods: Sixteen PD patients with MCI (PD-MCI), sixteen normal cognition PD patients (PD-NC), and 28 healthy controls (HCs) were included. The differences in the magnetic susceptibility and Radiomic indicators among groups and their correlations with Montreal Cognitive Assessment-Basic (MoCA-B) scores and Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) were analyzed. Receiver operating characteristic curves were used to evaluate the diagnostic performance. Results: Higher iron deposition was observed in the cortical and subcortical structures of the PD patients compared with HCs, including limbic system, orbitofrontal cortex, cuneus, red nucleus, and substantia nigra. Combined magnetic susceptibility and texture index in hippocampus achieved the best diagnostic performance (area under curves: 0.828) in differentiating PD-MCI from PD-NC. The magnetic susceptibilities of the substantia nigra, red nucleus, putamen, globus pallidus, hippocampus, and thalamus were negatively correlated with the MoCA-B scores (all p < 0.05), and of the putamen and amygdala were positively correlated with the UPDRS-III scores (both p < 0.05). Conclusion: Higher iron deposition was observed in the cortical and subcortical structures of the PD-MCI and PD-NC groups. The susceptibility values of vulnerable brain subregions shown significant correlation with MoCA-B and UPDRS-III. Together with the texture index, magnetic susceptibility values could provide robust performance in distinguishing PD-MCI patients from PD-NC.