CTA creates images of arteries throughout the body. A contrast medium (x-ray dye) is injected to make the blood vessels stand out. Pictures are then taken with the CT scanner. The CT images are processed by a computer to make a three-dimensional picture.

CTA may be used to:
Examine arteries in the abdomen, neck, lungs, pelvis, kidneys, or brain.
Look for an aneurysm (ballooning of the blood vessel wall) or dissection (tear).
See whether a stent (device used to keep an artery open) is working properly.
Detect damage to arteries due to injuries.
Gather details on blood vessels that supply tumors.
Drink only clear liquids for 6 hours before the procedure.
Tell your radiologist what medications, herbs, or supplements you take; if you are, or may be, pregnant; or if you are allergic to contrast medium or other medications.
Remove hair clips, jewelry, dentures, and other metal items that could show up on the x-ray.
You'll lie down on the scanning table. An IV (intravenous) line will be set up.
The scanning table will be positioned so that the part of your body being examined is inside the donut-shaped CT scanner.
One image may be taken to be sure you are positioned correctly for the test.
The IV will be hooked up to an automatic injection machine. This controls the timing and rate of injection. The injection may continue during part of the exam.
Contrast medium will be injected into a vein through the IV line. You may feel warmth through your body when the contrast material is injected.
You will need to remain still while the x-rays are being taken. Pillow and foam pads may be used to help you stay in position. You'll be told to hold your breath for 10 to 25 seconds at a time.
The whole procedure may take 10 to 25 minutes.
Potential risks and complications of CTA are minimal and include:
Problems due to contrast medium, including allergic reaction or kidney damage
Skin damage from leaking contrast fluid near IV site
Drink plenty of fluids to help flush the contrast fluid from your system.
You may eat as soon as you wish to.