Clinical Utility of Tectal Plate Measurements on Magnetic Resonance Imaging in Progressive Supranuclear Palsy

Background Midbrain atrophy is a characteristic feature of progressive supranuclear palsy (PSP), observed in PSP‐Richardson's syndrome (PSP‐RS) and to a lesser extent PSP‐parkinsonism (PSP‐P). Objective Our aim was to critically evaluate the utility of manual magnetic resonance imaging measurements of the midbrain tectal plate as a diagnostic biomarker in PSP. Methods Length of the tectal plate and width of the superior and inferior colliculi were measured in 40 PSP (20 PSP‐RS and 20 PSP‐P) patients and compared with 20 Parkinson's disease and 20 healthy control subjects. Results Tectal plate length was reduced in both PSP groups compared with Parkinson's disease and control subjects and was most abnormal in PSP‐RS followed by PSP‐P. Reduced tectal plate length was associated with worse PSP Rating Scale scores. Conclusions Simple manual measurements of tectal plate length show utility as a diagnostic biomarker in PSP, particularly for PSP‐RS.