Digital angiogram showing a narrowing (stenosis, upper centre) of the left common carotid artery in the neck of a 62-year-old woman. This is a stenosis of the left internal carotid, at the level of the carotid bifurcation, with a narrowing greater than 75 percent. This narrowing of the carotid artery is usually caused by a build up of plaque, causing atherosclerosis.