Three-dimensional ultrasonography of hydrocephalus.

We examined two infants with hydrocephalus using three-dimensional (3-D) ultrasonography. One infant had congenital hydrocephalus with a ventriculoperitoneal shunt. On 2-D ultrasonography, the shunt tube was shown only as "a point." However, on 3-D ultrasonography, we could easily see the three-dimensional position of the shunt tube, which was situated in the lateral ventricle. The other patient had hydrocephalus associated with an arachnoid cyst. We could understand the complex shape of the cyst and distinguish it from the third ventricle using 3-D ultrasonography. Thus, 3-D ultrasonography imaging is more useful than 2-D ultrasonography imaging in evaluating hydrocephalus.