Foramen of Munro – superior extension of suprasellar tumors, arachnoid cysts, colloid cysts, giant cell astrocytoma
Aqueduct – tectal plate glioma, superior extension of midline posterior fossa mass like brain stem diffuse astrocytoma, inferior extension of pineal region tumors
Fourth ventricle outlet – displacement in Chiari II
Spinal cord tumors
Hemorrhage or exudates or pial dissemination of tumors
Temporary – external drainage
Permanent – ventriculoperitoneal, ventriculoatrial or third ventriculostomy
Third ventriculostomy – puncture floor of third ventricle, CSF flows into suprasellar cistern
Noncommunicating hydrocephalus: temporal horns disproportionately dilated to lateral ventricle body, dilated anterior and posterior recess of third ventricles, inferior bowing of floor of third ventricle, transependymal edema, bulging fontanelles. Sulci and cisterns small or obliterated. Some less consistent findings: widened radius of frontal horn, dorsum sella erosion, copper beaten skull
Communicating hydrocephalus: general ventriculomegaly to normal study
< 2 years: benign enlargement of sulci is normal. Children can have prominent sulci without any underlying hydrocephalus. Concentrate on head size and cerebrum to rule out atrophy. Serial imaging helps to identify cause
Beyond 10 years, the sulci are less conspicuous, ventricles less prominent, this is normal. Basal cisterns SHOULD NOT be effaced.
Recurrence of hydrocephalus, fluid tracking along shunt tubing, calcification at either end of shunt due to fibrosis or inflammation, absence of T2 flow void across third ventriculostomy
Shunt infection – ventriculitis, cerebritis, possible fatal brain injury.