Stroke is the third-most-common cause of death, after heart attacks and cancer. To prevent stroke some doctors are using two tests that can better detect risk. One is the carotid ultrasound. It spots fatty plaque buildup in the carotid arteries on each side of the neck, which transport blood to the brain. When plaque and blood clots block blood flow, a stroke occurs. Carotid strokes may account for one-third to one-half of all strokes. The other test, called the ankle-brachial test, gives a reading on plaque buildup throughout the body’s arteries. It is a useful predictor of stroke and heart attacks, and it directly measures “peripheral vascular disease” or fatty deposits in leg arteries that can cause leg pain and difficulty walking.