In other cases further testing is needed. History and physical exam. A doctor will ask about symptoms of a stroke such as numbness or muscle weakness, speech or vision difficulties, or lightheadedness. Unfortunately, dangerous levels of disease sometimes fail to make a sound, and some blockages with a low risk can make the same sound. This is a painless, noninvasive test in which sound waves above the range of human hearing are sent into the neck.
Echoes bounce off the moving blood and the tissue in the artery and can be formed into an image.
Ultrasound is fast, risk-free, relatively inexpensive, and painless compared to MRA and arteriography. This can be used to confirm the findings of ultrasound imaging which can be uncertain in some cases. Arteriography is an X-ray of the carotid artery taken when a special dye is injected into the artery. A burning sensation may be felt when the dye is injected. An arteriogram is more expensive and carries its own small risk of causing a stroke.