Carotid ultrasound uses basic ultrasound technology to assess the arteries that supply blood to the brain. These are the carotid arteries, the vertebral arteries, and the basilar artery. This is a noninvasive, painless test that is done to check for narrowing, spasms, and even blockages of the arteries that provide the brain with its blood supply. This test is short, lasting only about 20-30 minutes. There is no special preparation required for this test. Following the test you may resume your normal daily activities as you had planned. The technician will perform the test and afterwards the physician will later discuss the results with you.