Multimodality Brain Imaging Markers in Progressive Supranuclear Palsy Subtypes and Parkinson's Disease

Background The new classification of progressive supranuclear palsy (PSP) subtypes necessitates identifying radiological biomarkers to support the clinical diagnosis. Objective The goal was to test if magnetic resonance imaging (MRI) morphometry, diffusion tensor imaging (DTI), susceptibility‐weighted imaging (SWI), or [18F]fluorodeoxyglucose ( 18F FDG)‐positron emission tomography (PET) differentiates PSP subtypes from each other or Parkinson's disease (PD). Methods Midbrain/pons (M/P) area ratio, middle/superior cerebellar peduncle (MCP/SCP) width ratio, magnetic resonance parkinsonism indices (MRPI and MRPI2) and midbrain antero‐posterior (AP) diameter were measured. Region of interest‐based DTI, SWI, and 18F FDG‐PET analyses were performed. Results Four PSP subtypes (n = 85) and 24 PD were studied. MRI morphometry and DTI could differentiate PSP‐Richardson syndrome (PSP‐RS) from PSP‐parkinsonism, PSP‐postural instability, and PD (area under curve >0.7). SWI did not differentiate among PSP subtypes or PD. 18F FDG‐PET distinguished PSP from PD. Conclusions MRI morphometry and DTI differentiated PSP‐RS from the other common PSP subtypes and PD and may be tested as a radiological marker of PSP‐RS in larger studies.