Carotid stenting is the insertion of a small metal tube known as a stent to widen the carotid artery (the vessel responsible for blood flow to the brain) if it has been hindered by plaque buildup. During the procedure, the physician localizes narrow, weak blood vessels by injecting a dye into the veins, performing a fluoroscopy (a test providing a live x-ray image) to detect blockage in the veins. This helps guide the physician in proper placement of the carotid stent. Once the stent has been put into place with a balloon-like tool, it expands to compress the plaque onto the walls of the artery. The stent is made of stainless steel mesh material to prevent rusting and allow for proper expansion. Once the artery has widened the balloon is removed and the stent is left inside permanently. The entire procedure normally lasts about two hours.