Extensive subarachnoid haemorrhage within bilateral cerebral sulci (relatively symmetric), Sylvian fissures, interhemispheric fissure, basal cisterns and fourth ventricle. The cerebral sulci are effaced.
Subdural haematomas overlie bilateral cerebral hemispheres measuring up to 7 mm in maximal depth overlying the posterior parietal lobes. Blood also layering along the right tentorium cerebelli.
Extension of the cerebellar tonsils 10mm below the foramen magnum. Narrow ventricles likely due to raised intracranial pressure. Small locules of gas within the left middle cranial fossa.
Supratentorial grey-white differentiation is reduced but not completely absent and the brainstem is of relatively low attenuation compared with cerebellar parenchyma.
Conclusion
- Extensive bilateral subarachnoid and subdural haemorrhage. Loss of grey-white differentiation, swelling and cerebellar tonsil herniation indicate diffuse cerebral edema.
- Minimally displaced fracture within the occipital bone with extension into the left parietal bone. Small locules of intracranial gas and adjacent haemorrhage.