Carotid artery disease. Coloured 3D computed tomography (CT) scan and angiogram, showing a frontal view of the cervical spine and carotid arteries of a 65-year-old man. The angiography (use of a contrast medium to highlight blood vessels) shows irregularities in the carotid arteries (left and right) that may indicate the presence of arterial disease and atheromatous plaques causing narrowing (stenosis) of the blood vessels. This could lead to a stroke if the blood supply to the brain is interrupted. The irregularity is particularly pronounced at the level of the left internal carotid artery.