Which diagnostic procedure uses x-ray imaging of the blood vessels in the lungs after the injection of contrast material?

• A. Pulmonary Angiography
• B. Pulmonary Function Tests (PFTs)
• C. Sigmoidoscopy
• D. Thoracoscopy

Answer: (A)

Imaging the lung’s blood vessels with contrast-enhanced X-ray studies is the defining idea here. In a pulmonary angiography, a catheter is guided to the pulmonary arteries and iodinated contrast is injected while fluoroscopy takes live images. This highlights the vasculature, showing vessel size, blockages, leaks, or malformations, and is particularly used to evaluate conditions like pulmonary embolism or vascular anomalies.

The other options don’t fit because they assess different aspects: pulmonary function tests measure lung function (volumes, capacities, flows) rather than the blood vessels; sigmoidoscopy looks at the lower colon with a scope; thoracoscopy is a surgical visualization of the chest cavity.