Why is there intraventricular haemorrhage?
Intraventricular extension can occur in subarachnoid haemorrhage most commonly by reflux. Note how there is increased volume in the fourth and third ventricles compared to the lateral ventricles.
Extensive subarachnoid blood is demonstrated within the suprasellar, ambient, and quadrigeminal plate cisterns and the sylvian fissures bilaterally. Large volume of blood also fills prepontine cistern and extends through foramen magnum. Smaller volume of subarachnoid blood is identified within the cerebral sulci bilaterally, predominantly in the inferior frontal regions.