The Nature of the Drug: Gadolinium is a chemical element that is used as a contrast agent in magnetic-resonance imaging (MRI) and magnetic-resonance angiography (MRA) scans. The patient is injected with a gadolinium-based dye before scanning, causing abnormalities in internal organs, blood vessels, and soft tissue to be visible in the scan. Five gadolinium-based contrast agents are approved in the United States.
