What is ventricular shift?

Ventricular shift is the lateral displacement of the cerebral ventricles away from a focal or generalized brain lesion. It is caused by the mass effect of the lesion, which compresses the brain tissue and displaces the cerebrospinal fluid (CSF)-filled ventricles. Ventricular shift can be seen on imaging studies such as CT and MRI scans, and it is often used to help localize a brain lesion.

Ventricular shift is more commonly seen with supratentorial (above the tentorium cerebelli) lesions than with infratentorial (below the tentorium cerebelli) lesions. This is because supratentorial lesions are more likely to cause mass effect due to the limited space in the cranium. Infratentorial lesions, on the other hand, have more room to expand without causing significant mass effect.

The direction of ventricular shift can also be helpful in localizing a brain lesion. For example, a lesion in the right hemisphere will typically cause a leftward ventricular shift, while a lesion in the left hemisphere will typically cause a rightward ventricular shift.

The degree of ventricular shift can also provide some information about the severity of a brain lesion. A large ventricular shift typically indicates a large or severe brain lesion, while a small ventricular shift may indicate a small or mild brain lesion.

Ventricular shift is an important finding on imaging studies of the brain, and it can be helpful in localizing and diagnosing brain lesions.