Neuroradiology

Traumatic intracranial haemorrhage

Intracranial hemorrhage resulting from trauma, may be extra- or intra-axial. Extra-axial haemorrhage includes epi- and subdural haematomas and subarachnoid and intraventricular haemorrhage. Epidural haematomas are most often associated to skull fractures and develop acutely. Subdural haematomas are most often seen without fracture and develop as a consequence of shear stress forces leading to rupture of subdural bridging veins. Subdural haematomas, which may develop subacutely or chronically or following a delay after trauma, must be considered in the event of clinical recurrence and must be sought with repeated imaging in elderly patients. Subarachnoid and intraventricular haemorrhage is often associated with severe cranial trauma. In the mildest forms the blood collects in the interpeduncular cistern and is often associated with the presence of blood in the ventricular occipital horns. Even this mild form usually reflects severe trauma. Imaging details on all types of haemorrhages are discussed under specific entry words.

Intra-axial haemorrhagic foci usually represent contused parenchymal tissue rather than true haematomas. Sometimes the haemorrhagic area extends, and this is believed to be the result of progressive haemorrhagic degeneration of primarily necrotic tissue. A particular type of intra-axial haemorrhage developing by an indirect post-traumatic mechanism is Duret's midbrain haemorrhage. This develops on an ischaemic basis following compression of perforating arteries in the interpeduncular cistern owing to caudal displacement of the upper brain stem in case of severe brain swelling.

GS