Among initial imaging studies for suspected PE, which test is commonly performed but not definitive?

• A. CXR
• B. CT Angio
• C. V/Q scan
• D. Pulmonary Angiography

Answer: (A)

The key idea is that chest X-ray is commonly the first imaging test done when pulmonary embolism is suspected because it’s quick, widely available, and helps rule out other lung conditions. However, it does not confirm or exclude a PE. Its findings are non-specific or even normal in many patients with PE, so a normal or non-diagnostic chest X-ray cannot rule out the diagnosis. That’s why further imaging that can directly visualize the pulmonary arteries, like CT pulmonary angiography, is used to make or exclude the diagnosis. A ventilation–perfusion scan is another option when CT is not suitable (for example, contrast allergy or pregnancy) and can indicate a mismatch suggestive of PE, though it is less definitive in some settings. Pulmonary angiography is the invasive gold standard but is not used as the initial test due to its risks and because noninvasive options are usually sufficient.