Ventriculomegaly

Ventriculomegaly is the radiologic enlargement of the brain’s ventricular system, most often the lateral ventricles. In prenatal imaging, it is defined when the atrial width of the lateral ventricles measures greater than about 10 millimeters. In postnatal imaging, ventriculomegaly can reflect hydrocephalus or brain parenchymal loss (ex vacuo) and should be interpreted in the clinical context.

Causes of ventriculomegaly are varied. Congenital examples include obstructive processes such as aqueductal stenosis, stenosis at the foramina of Luschka or Magendie, and other developmental anomalies; infectious or inflammatory conditions; and lesions that affect CSF circulation. In infants and children, intraventricular hemorrhage or perinatal infections can contribute. Acquired causes include brain atrophy from neurodegenerative disease or aging, tumors, and conditions that impair CSF absorption. Ventriculomegaly may occur with or without associated brain abnormalities.

Diagnosis and imaging assessment rely on ultrasound for prenatal screening and follow-up, with magnetic resonance imaging (MRI) or computed tomography (CT) providing detailed evaluation after birth. Clinicians distinguish simple ventriculomegaly from hydrocephalus by assessing signs of raised intracranial pressure, sulcal patterns, and CSF distribution; index measurements such as Evans index can aid in adults. Examination should also consider ex vacuo enlargement due to parenchymal loss.

Management is tailored to cause and severity. Mild, isolated ventriculomegaly may be monitored with serial imaging and genetic/cause evaluation. Progressive or symptomatic ventriculomegaly or hydrocephalus may require CSF diversion, such as ventriculoperitoneal shunting or endoscopic third ventriculostomy, alongside treatment of the underlying condition.

Prognosis varies with etiology and timing of intervention; isolated prenatal cases may have good outcomes, while those associated with other anomalies carry greater risk for neurodevelopmental impairment.