Differential Neural Substrates of Freezing of Gait in Cerebral Small Vessel Disease and Parkinson Disease: A Dual-tracer PET Study

FOG in PD and CSVD is associated with divergent dopaminergic and metabolic imaging patterns. PD-FOG is characterized by marked nigrostriatal DAT reduction, whereas CSVD-FOG shows relatively preserved DAT binding compared with PD and distinct whole-brain-normalized 18F-FDG uptake patterns, suggesting involvement of neural networks beyond primary nigrostriatal dopaminergic pathways. These imaging differences may support etiology-informed diagnostic considerations and individualized management strategies.