Why is a carotid artery duplex scan used?

A carotid artery duplex scan (a type of vascular ultrasound study) is used to assess occlusion (blockage) or stenosis (narrowing) of the carotid arteries of the neck and/or the branches of the carotid artery. Plaque (a buildup of fatty materials), thrombus (blood clot), and other substances in the bloodstream may cause a disturbance in the blood flow through the carotid arteries.

When the carotid arteries become blocked, symptoms may include dizziness, confusion, drowsiness, headache, momentary blindness in one eye, and/or a brief loss of ability to speak or move. These symptoms may indicate early warning signs of a possible stroke (brain attack, or cerebrovascular accident [CVA]).

A carotid artery duplex scan may also be performed when no symptoms of occlusion are present, yet an abnormal blood flow sound called a bruit is heard with a stethoscope over the artery. This may indicate a possible condition of abnormal blood flow in the artery.

Additional reasons for the procedure include, but are not limited to, the following:

• evaluation of previous procedures to restore blood flow to the area (such as an angioplasty to open up an artery that was blocked or surgery to bypass a blocked artery)
• evaluation of carotid blood flow prior to a major cardiovascular surgical procedure, such as coronary artery bypass grafting or heart valve repair/replacement
• location of a hematoma (a collection of clotted blood that may slow and eventually stop blood flow)
• detect dissection of the carotid artery, a split between layers of the artery wall that may lead to obstruction of blood flow or a weakening of the wall of the artery

There may be other reasons for your physician to recommend a carotid artery duplex scan.