CT (computed tomography) angiography (CTA) is an examination that uses x-rays to visualize blood flow in arterial vessels throughout the body, from arteries serving the brain to those bringing blood to the lungs, kidneys, and the arms and legs. CT combines the use of x-rays with computerized analysis of the images. compared to catheter angiography, which involves injecting contrast material into an artery, CTA is much less invasive and a more patient-friendly procedure; contrast material is injected into a vein rather than an artery. This exam has been used to screen large numbers of individuals for arterial disease.