Aqueductal stenosis | Figure 1
Aqueductal stenosis
Fetal MRI (image 1) shows massive enlargement of the lateral ventricles and stenosis (arrow on MRI) of the aqueduct of Sylvius.
Aqueductal stenosis is one of the most common causes of fetal hydrocephalus. The narrowing of the aqueduct of Sylvius causes enlargement of the lateral and third ventricles. However, the fourth ventricle is normal in size as it is distal to the stenosis. Patients are treated with a ventriculoperitoneal shunt and may also undergo 3rd ventriculostomy.