Abstract
Focal post traumatic mass lesions such as contusions and intracerebral haematomas are common, and often difficult for neurosurgeons to manage, because little is known of their pathophysiology. We have mapped cerebral blood flow, and studied small vessel ultrastructure at different time points within the first three weeks of head injury, in patients with these lesions. A zone of ischaemic brain is always present around these lesions, and persists for weeks or months. This accords with astrocyte swelling and microvascular compression seen on electron microscopy. Focal zones of hyperaemia were also present in 42% of patients, within the first two weeks of injury, and this appeared only within apparently normal tissue as judged by late MRI or CT.