False-colour angiogram of the abdominal aorta, revealing an obstructed right iliac artery due to thrombus formation. The obstruction is apparent because of the total absence of the outline of the artery (coloured pink) at bottom left. The abdominal aorta (centre) divides (bifurcates) into the left & right iliac arteries, which supply the legs. Here, the left iliac artery is shown (at right), yet there is no equivalent at left of image. Aniography is an X-ray technique which employs the prior injection of an iodine-based, radio-opaque contrast medium to outline various arteries of the body. The method varies according to the site of arteries within the body.