A carotid ultrasound is a noninvasive imaging test that uses sound waves to evaluate the carotid arteries in the neck, which supply blood to the brain. The test helps detect plaque buildup, narrowing or blockages that may increase the risk of stroke or transient ischemic attacks (TIAs). By assessing blood flow and artery structure, a carotid ultrasound allows physicians to identify vascular disease early, monitor existing conditions and guide preventive or treatment strategies to support long-term vascular and neurological health.