Carotid artery stenoses are the cause of approx. 15% of cerebral infarctions which are often difficult and prone to recur. Endarterectomy of a carotid artery stenosis that has caused disturbances of the cerebral circulation is an effective remedy: operating six tight stenoses will prevent one cerebral infarction. One of the most promising methods to identify the patients having the highest risk of cerebral infarction is noninvasive imaging of the stenosis. Since the detection of a significant carotid artery stenosis is predictive of an increased risk of cerebral and cardiac infarction, the vascular risk factors should be identified on an individual basis and treated effectively. Screening of asymptomatic carotid artery stenoses is, however, not yet recommended.