Cerebral infarct makes up about 60-70% of all "strokes". Acute infarction is characterised by acute swelling and mass effect of the affected areas, radiologically and pathologically. Notice the mid-line shift, the poor demarcation between grey and white matter, the squashing of the lateral ventricle and uncal herniation.

Such large infarct, affecting most of the cerebral hemisphere, is usually due to atherosclerotic thrombotic occlusion of the common carotid artery outside the brain. Remember the extracranial vessels (common carotid arteries) are as important as the extracranial vessels in causing strokes. In addition to causing infarcts, platelet emboli shedded from ulcerative plaques in the common carotid arteries can also lead to hemorrhagic embolic infarctions.