CT
Global diffuse oedema and loss of normal grey-white differentiation is present. Hypoattenuation of the cerebral hemispheres and especially basal ganglia with sparing of the cerebellum is seen along with hyperdense falx cerebri and tentorium cerebelli relative to brain parenchyma, giving the appearance of pseudosubarachnoid haemorrhage. These appearances are consistent with hypoxic-ischaemic brain injury.
There is marked increased mass effect with tonsillar and uncal herniation, and slit-like effacement of the lateral and third ventricles. No midline shift. No intracranial haemorrhage.