The callosal angle has been described as useful in discriminating iNPH-Hakim–Adams Syndrome from ventricular dilation secondary to atrophy. the angle should be measured on a coronal image perpendicular to the anterior commissure – posterior commissure (AC-PC) plane at the level of the posterior commissure.

A normal value is typically between 100-120°. In patients with iNPH that value is lower, between 50-80°