No acute intra or extra-axial haemorrhage or collection. There is diffuse cerebral oedema with significant positive mass effect causing diffuse sulcal effacement and near complete effacement of the cisterns. Partial effacement of the ventricular system. No hydrocephalus. The cerebellar tonsils have herniated up to 9 mm below the level of the foramen magnum.
There is diffusely reduced supratentorial grey-white matter differentiation with apparent relative hyperattenuation of the subarachnoid spaces (pseudosubarachnoid haemorrhage) and the cerebellum (reversal sign).
The superior ophthalmic veins are prominent bilaterally, and the distal aspects of the optic nerve sheaths are also prominent. No acute skull fracture or surface collection. Mucosal thickening in the ethmoid air cells, maxillary sinuses, and sphenoid sinus. The frontal sinus and mastoid air cells are well pneumatised.
Features of diffuse cerebral oedema due to diffuse hypoxic ischaemic injury. Significant positive mass effect and cerebellar tonsillar herniation. No hydrocephalus.