Which imaging technique involves x-ray imaging of blood vessels after injection of contrast material?

• A. MRI
• B. Angiography
• C. PET Scan
• D. EEG

Answer: (B)

The main concept being tested is visualizing blood vessels by using X-ray imaging after injecting a contrast agent. This technique, angiography, involves injecting a radiopaque contrast material into the bloodstream and then capturing X-ray images (often in real time with fluoroscopy) so the vessels—arteries and veins—become visible against the surrounding tissues. It may be performed via catheter into a specific artery and can be enhanced with digital subtraction to better highlight the vessels by removing overlying structures. This approach is distinct from MRI, which relies on magnetic fields to image tissue and may use gadolinium but does not depend on X-ray visualization of vessels; PET scans map metabolic activity using radioactive tracers; and EEG records electrical brain activity rather than blood vessel anatomy.