Duplex Carotid Doppler: This study is often part of the typical work-up for stroke and stroke-like symptoms. Carotid ultrasound detects narrowing or blockage in the neck arteries, which ultimately supply the brain. Significant narrowing of the carotid arteries may lead to stroke and may require surgery or stenting. Ultrasound of the carotids and neck vessels is also used to evaluate dizziness particularly if it is associated with movement of the arm, a condition known as subclavian steal syndrome. Your doctor may also order a carotid ultrasound as a screening test if you have significant risk factors for cardiovascular disease.