Which procedure is used to visualize blood vessels by recording images after contrast?

• A. MRI
• B. X-ray
• C. Angiography
• D. Ultrasound

Answer: (C)

Visualizing blood vessels after injecting contrast relies on highlighting the vessel lumens so they can be seen clearly on imaging. Angiography is the study designed for this: a radiopaque contrast agent is introduced into the bloodstream, and images are recorded—typically with X-ray fluoroscopy—so the outline of the vessels stands out. This makes it possible to assess the size, course, and any blockages or malformations of the vascular system. Other modalities can depict vessels in different ways (MR angiography with MRI, Doppler or color flow with ultrasound), but the classic procedure described—recording images after contrast to visualize vessels—is angiography.