Strokes are one of the most frightening medical problems because they are unpredictable and often deadly.

Unlike other serious conditions such as heart disease, there has never been a reliable diagnostic test that can reveal who is a likely candidate for one of these “brain attacks,” the Newsmax Health reported.

Carotid artery disease, a condition in which plaque builds up inside the carotid arteries that supply blood to the brain, causes more than half the strokes in the U.S.

In recent years, new techniques have been developed to identify who’s at risk and to treat carotid artery blockages before a stroke occurs.

One of the best ways to detect carotid artery disease is with an ultrasound scan, a painless, noninvasive test. Using a probe that sends sound waves into the neck and a computer that translates the effects into images that can be seen on a screen, the test can gauge the speed of blood flow through the carotid arteries, anatomic images of the arteries, and a sense of how narrow the arteries are and how much plaque is present.

Doctors typically reserve this scan for people over 50 who have a family history of cardiovascular disease or peripheral vascular disease, or symptoms of a transient ischemic attack (often called a mini-stroke) such as sudden weakness or numbness on one side of the body, trouble speaking, or sudden vision problems, dizziness, or loss of balance. However, if you don’t fit any of these categories but are worried about having a stroke, your physician might agree to give you this test if you request it. 

“If the person is asymptomatic and the carotid artery is 70 percent blocked, we might consider surgery,” says Paul Lucas, M.D., a vascular surgeon and director of the vascular laboratory at Mercy Medical Center in Baltimore.

With a carotid endarterectomy, a surgeon opens the carotid artery and removes plaque and the artery’s inner lining. With a newer procedure called carotid artery stenting, a surgeon places a stent in the blocked artery to open it and restore blood flow.