False-colour arteriograph (angiograph) of a normal right lung, showing the branching tree" of arteries arising from the pulmonary artery which supplies blood to the lung. Arteriography is the x-ray examination of arteries that have been outlined by prior injection of a radio-opaque contrast medium; the technique is often used to demonstrate the site & extent of atheroma (arterial degeneration due to formation of fatty plaques & scar tissue - common in Western countries). Also visible are the ribs, connecting with the spine on right of image."