A carotid angiogram is a test that uses X-rays to show narrowing or blockage in the carotid arteries. The carotid arteries supply blood to parts of the neck, head and brain. (see fig. 1). Narrowing or blockage of the carotid artery can be caused by fatty plaque that builds up inside the inner lining of the artery (see fig. 2). This process is called atherosclerosis and it can reduce blood flow to the brain.

To perform a carotid angiogram, a catheter is guided into the base of your carotid arteries (see fig. 3). The catheter injects a dye that is visible with X-rays into the bloodstream. Areas of narrowing or blockage in the carotid arteries are shown on a video screen (see fig. 4).

Figure 1: Normal blood supply to the brain.

Figure 2: Carotid artery narrowed by atherosclerosis.

Figure 3: Catheter guided into the base of the carotid artery.