Which imaging modality visualizes pulmonary arterial occlusions in pulmonary embolism?

Which imaging modality visualizes pulmonary arterial occlusions in pulmonary embolism?

• A. It visualizes pulmonary arterial occlusions
• B. It measures arterial blood gas
• C. It is the only test used for PE
• D. It does not require contrast

Answer: (A)

The main idea is that you want an imaging test that shows the actual blockages inside the pulmonary arteries. The best fit is CT pulmonary angiography, which uses intravenous contrast to opacify the pulmonary arteries. Because the arteries are filled with contrast, an embolus appears as a filling defect—an area where contrast is not present—directly revealing the occlusion and its location. This direct visualization is why this modality is sought when pulmonary embolism is suspected. Other options don’t show the occlusion itself. Arterial blood gas measures oxygen and carbon dioxide levels, not anatomy. The statement that it’s the only test for PE is incorrect—diagnosis often involves multiple approaches, including clinical assessment, D-dimer testing, leg ultrasounds for DVT, and sometimes alternative imaging like ventilation-perfusion scans or MR options. And while some imaging methods can work without iodinated contrast, CT pulmonary angiography relies on contrast to visualize the arteries and the occlusion clearly.

The main idea is that you want an imaging test that shows the actual blockages inside the pulmonary arteries. The best fit is CT pulmonary angiography, which uses intravenous contrast to opacify the pulmonary arteries. Because the arteries are filled with contrast, an embolus appears as a filling defect—an area where contrast is not present—directly revealing the occlusion and its location. This direct visualization is why this modality is sought when pulmonary embolism is suspected.

Other options don’t show the occlusion itself. Arterial blood gas measures oxygen and carbon dioxide levels, not anatomy. The statement that it’s the only test for PE is incorrect—diagnosis often involves multiple approaches, including clinical assessment, D-dimer testing, leg ultrasounds for DVT, and sometimes alternative imaging like ventilation-perfusion scans or MR options. And while some imaging methods can work without iodinated contrast, CT pulmonary angiography relies on contrast to visualize the arteries and the occlusion clearly.