Hydrocephalus

1-Definition:Means one of the following definitions

-Water on the brain.

-CSF within dilated ventricles.

-Increase intra ventricular pressure.

2-Radiological signs in plain skull film:

-Increased cranio-facial ratio.

-Widened sutures.

-Bulging fontanelles.

-Erosion of dorsum sellae(seen after closure of fontanelles).

-Silver beaten appearance in chronic cases.

3-Hydrocephalus versus brain atrophy:

-By using sagital MRI in case of hydrocephalus.

-Look for the following

# Enlargement of the anterior and posterior recesses of the lateral ventricles.

# Ballooned third ventricle.

# Downward convexity of the floor of the third ventricle.

# Dilated temporal horns.

The most important issue here is effacement of cortical sulci while in cortical atrophy, the cortical sulci is also dilated.

Also, peri ventricular edema is seen in case of hydrocephalus but not in brain atrophy.