CTA is a type of exam that uses CT technology to look at blood vessels. CTA is typically used to examine blood vessels in the brain, neck, abdomen and chest. CT (Angiography) is a type of medical test that combines a CT scan with an injection of a special dye to produce pictures of blood vessels and tissues in a part of your body. The dye is injected through an intravenous (IV) line started in your arm or hand. A computerized tomography scan, or CT scan, is a type of X-ray that uses a computer to make cross-sectional images of your body. The dye injected to perform CT angiography is called a contrast material because it ""lights up"" blood vessels and tissues that are being studied.