A computed 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.
Magnetic resonance imaging (MRI) is a procedure that uses a large magnet, radio waves and a computer to create detailed images of organs and tissues in the body. It’s used to diagnose problems in many areas of the body.