Superior diagnostic value of susceptibility mapping over ADC in differentiating multiple system atrophy from Parkinson’s disease

Motivation: Distinguishing MSA-p from PD based on clinical diagnostic criteria using ADC remains challenging. Recent studies have evaluated utility of QSM for diagnosis. However, direct comparison of diagnostic performance between ADC and susceptibility maps has not yet been conducted. Goal(s): This study aims to compare diagnostic accuracy of ADC-based qualitative diagnosis with susceptibility map based quantitative differentiation. Approach: Significant clusters were generated from susceptibility maps to evaluate diagnostic accuracy. ROI analysis and age-related effects were investigated using susceptibility source separation technique. Results: AUC was higher for susceptibility map-based thresholding compared to neurologist diagnosis using ADC. Age-related decrease in diamagnetic susceptibility was observed in MSA-p. Impact: Diagnostic accuracy of susceptibility map for differentiating MSA-p from PD was evaluated, revealing higher accuracy when using susceptibility map-based thresholding compared to ADC-based qualitative assessment. We propose clinically important regions for distinguishing MSA-p when utilizing susceptibility-based imaging.