What is the main finding?
Non-communicating obstructive hydrocephalus. Marked dilatation of the lateral ventricles, third ventricle and superior portion of the aqueduct of Sylvius.
What is the diagnosis and what are the causes of this condition?
Aqueductal stenosis can be either congenital or acquired (tectal mass / tumour or subarachnoid haemorrhage / ventriculitis).
Non-contrast CT demonstrates marked dilatation of the lateral and third ventricles as well as the superior part of the aqueduct of Sylvius. The fourth ventricle posterior fossa basal cisterns are unremarkable, and the cortical sulci are effaced. There is no transependymal oedema. The septum pellucidum is fenestrated.