A stroke is actually a "brain attack" where there is an interruption of normal blood flow to the brain, causing brain cell death. Stroke can lead to impairment of functions such as speech, vision or movement, and coma or death. The screening for brain attack uses noninvasive technology to determine the degree of atherosclerotic stenosis at the carotid bifurcation.

Patients with a significant carotid stenosis who have had a transient ischemia attack (TIA) or minor stroke, are at a high risk for having a major stroke in the next 12 to 24 months. In addition, patients who have significant narrowings of the arteries but no symptoms are also at risk. In fact, at least 50 percent of the time, their first symptom is not a minor event, but rather a stroke.