What are the radiological features and clinical significance of ex vacuo ventriculomegaly?

Ex vacuo ventriculomegaly is characterized by enlarged ventricles due to cerebral atrophy, with concurrent prominence of both sulci and ventricles on imaging. Key diagnostic features include normal or decreased intracranial pressure and the absence of transependymal flow of CSF. It is important to differentiate it from obstructive hydrocephalus, where ventriculomegaly is due to CSF flow obstruction, and normal pressure hydrocephalus, which presents with clinical symptoms such as gait disturbance, dementia, and urinary incontinence. Recognizing these differences is crucial to avoid unnecessary shunting procedures.