Midbrain area and the hummingbird sign from brain MRI in progressive supranuclear palsy and idiopathic normal pressure hydrocephalus
BACKGROUND AND PURPOSE: The main radiological finding in progressive supranuclear palsy (PSP) is reduced midbrain volume. Both qualitative (e.g., hummingbird sign) and quantitative (e.g., area measurements) markers have been noted. Recent studies have shown a similar reduction also in idiopathic normal pressure hydrocephalus (iNPH). The purpose was to investigate the reliability and accuracy of th