Computed tomography (CT) is a widely available, rapid and readily accessible technique for imaging of the brain by means of which other disorders, such as haemorrhage, can be excluded in patients with the signs of an acute cerebral infarction. Recently, CT perfusion and CT angiography have become available for this clinical application. These investigations can be performed in the same session as conventional CT, without significant delay. A combined CT protocol provides information on both cerebral perfusion and the patency of the extra- and intracranial arteries and can therefore yield valuable additional information in the diagnostic work-up and treatment of patients with acute cerebral ischaemia. Current and future research will have to determine the definitive value of these techniques in clinical practice.