The degree of risk of bilateral carotid atherosclerosis with plaque formation is based on a combination of plaque thickness and stability. If the plaque is more than 2.5 mm, or if it is unstable, then it is more dangerous. Usually, if the thickness of plaque found in ultrasound examination is more than 2.5 millimeters, it belongs to the larger plaque. If the atherosclerotic plaque in both carotid arteries is larger, it is very likely to cause insufficient blood supply to the brain, and thus cerebral infarction occurs, which is life-threatening in acute attack. Ultrasonography can be used to determine the composition of atherosclerotic plaques through two-dimensional ultrasound or ultrasonography, if it shows non-strong echoes or rich enhancement after ultrasonography, it means that the plaques are unstable plaques, which are prone to hemorrhage or fall off, resulting in serious complications, which are more dangerous and need timely treatment.