The non-contrast study demonstrates a large volume of intraventricular haemorrhage and marked ventricular enlargement even allowing for the patient's age. Intraventricular haemorrhage is seen in all the ventricles and extends into the sylvian fissures and basal cisterns. There is sulcal effacement particularly inferiorly with early loss of normal grey-white matter differentiation. No cerebellar tonsillar herniation.
A slightly hyperdense suprasellar mass measures ~3cm which is likely a giant aneurysm of the anterior circulation and the cause for the intraventricular haemorrhage.
Conclusion
Large volume intraventricular haemorrhage with hydrocephalus. The haemorrhage is likely secondary to a ruptured giant anterior circulation aneurysm.