[Duplex ultrasound for diagnosis of carotid stenosis. Detecting stroke candidates].

In the hands of an experienced examiner, and with consideration being given to defined criteria, duplex sonography of the extracranial arteries supplying the brain is a valid, noninvasive, nonstressful, reproducible and comparatively inexpensive examination procedure. The indication for this examination is established after a cerebral ischemic event, or in patients with an appropriate risk profile. Nevertheless, anatomical variants or technical problems make necessary a further diagnostic work-up in the form of MR or conventional angiography.