In hydrocephalus, ventriculomegaly is typically described with ventricular diameters of approximately what measurement?

• A. 10 to 15 mm
• B. 5 to 7 mm
• C. 20 to 25 mm
• D. 0 to 2 mm

Answer: (A)

In hydrocephalus, ventriculomegaly means enlargement of the lateral ventricles, which is assessed by measuring the atrial width on ultrasound. The normal atrial width in fetuses/newborns is up to about 10 mm; when it exceeds this, ventriculomegaly is present. Typically, mild to moderate dilation falls in the roughly 10 to 15 mm range, which is why that measurement best describes ventriculomegaly. Values smaller than this (5–7 mm) are usually normal or non-dilated, while much larger measurements (20–25 mm) indicate more severe dilation. So 10 to 15 mm captures the common range used to describe ventriculomegaly in hydrocephalus.