Stroke represents a clinical syndrome of rapid onset of focal or sometimes global cerebral deficit with a vascular cause, lasting more than 24 hours or leading to death. Eighty per cent of all strokes are ischaemic, 15% are due to intracerebral haemorrhage, and 5% to subarachnoid haemorrhage. Correct diagnosis is important because treatment options for ischemic stroke may be contraindicated in case of intracerebral haemorrhage. Such exact diagnosis requires state-of-the-art imaging of the brain. But which kind of imaging, how quickly should it be done, should this include imaging of cerebral blood flow, and what is the most cost effective approach? Answering these questions may help to further narrow the gap between experimental and clinical research as well may substantially improve the patient's care.