Mapping neuromelanin loss in clinically uncertain parkinsonism differentiates neurodegenerative from non-neurodegenerative

Brain dopamine transporter SPECT imaging is routinely used to assess striatal dopaminergic deficit in the differentiation of essential tremor from degenerative parkinsonism in clinically uncertain parkinsonism (CUP). Neuromelanin (NM)-MRI detects nigral depigmentation with good diagnostic accuracy in confirmed Parkinson’s Disease; but its diagnostic value in CUP is unclear. Using voxel-based analysis following optimised automatic registration, we investigated the topography of NM loss in CUP, and show that voxels that best discriminate between non-neurodegenerative and neurodegenerative CUP are co-located in the dorsolateral substantia nigra.