Current research of idiopathic normal pressure hydrocephalus: Pathogenesis, diagnosis and treatment

Figure 1 head magnetic resonance imagines. A: Axial head magnetic resonance imaging of idiopathic normal pressure hydrocephalus. Evans Index (EI) = maximum width of the frontal horns of the lateral ventricles/maximal internal diameter of the skull at the same level (A/B). EI > 0.3 is a significant finding suggestive of idiopathic normal pressure hydrocephalus; B: Coronal head magnetic resonance imaging of idiopathic normal pressure hydrocephalus. This image shows narrowing of the fornix region (white oval) and widening of the bilateral sylvian fissures (white arrows); C: Coronal magnetic resonance imaging at the anterior commissure perpendicular to the line connecting the anterior and posterior commissures. Z-Evans Index (zEI) = width of the frontal horn of the lateral ventricle/median intracranial diameter (B/A). Brain/ventricle ratio (BVR) = intracranial width immediately above the lateral ventricles/anterior horn width of the lateral ventricles (C/B). Scores of zEI > 0.42 and BVR < 1.0 are significant findings suggestive of idiopathic normal pressure hydrocephalus.