Back to Rapid Cardiology The two carotid arteries are the main vessels that supply blood to the brain. They originate from the main arteries of the body (the aorta and brachiocephalic artery) in the chest and travel up through the neck and into the skull. Atherosclerosis of the right or left carotid artery is the most common cause of a stroke. A carotid duplex scan is a technique to take a picture of these arteries using sound waves (ultrasound). A sound-wave transducer is placed gently on the neck. The walls and interior of the artery are visualised and the velocity…