Neuromelanin-Sensitive MRI as Biomarker of Phenoconversion from Pure Autonomic Failure to Central Synucleinopathies

Motivation: Pure autonomic failure (PAF), a peripheral synucleinopathy, is associated with a high risk of progressing to central synucleinopathies, highlighting the need for early detection. Goal(s): To assess neuromelanin-sensitive MRI contrast in the substantia nigra (SN) and locus coeruleus (LC) of PAF patients to identify early neurodegenerative changes. Approach: PAF patients were divided into high-risk and low-risk groups, and we compared contrast ratios in the SN and LC among these groups and healthy controls. Results: High-risk PAF patients exhibited significantly lower contrast ratios in the SN and LC compared to controls, indicating early neurodegenerative changes. Impact: This study highlights the potential of neuromelanin-sensitive MRI as an early biomarker for neurodegenerative changes in high-risk PAF patients, aiding in the timely detection and intervention for central synucleinopathies, such as Parkinson disease.