Carotid artery stenosis is an ischemic cerebrovascular disease, and many ischemic strokes are caused by carotid stenosis. If there is a sudden appearance of slurred speech, blurred vision and limb weakness, you need to be highly alert, because these are often signs of the presence of carotid stenosis. Carotid stenosis can cause cerebral infarction: The most common lesion of carotid artery is carotid stenosis, which can easily lead to cerebral infarction, which is often called cerebral thrombosis. Ischemic cerebral infarction caused by cerebrovascular blockage can first appear as coma or even death if it is serious, and there are different symptoms depending on the different parts of the blocked blood vessels and the different brain areas where the infarction occurs. Sometimes there can be hemiplegia, aphasia, hemianesthesia or hemianopsia, etc… Carotid ultrasound can be used to initially screen for carotid stenosis: the first and most basic test is carotid ultrasound, which is also the cheapest, non-invasive and quick, and even many hospitals have fewer patients queuing for the same day results. This is a preliminary and most basic screening tool, and is also relatively accurate. Once the carotid ultrasound reveals the presence of carotid artery stenosis, further and more precise tests may be required to determine which means of treatment to take.