Question:medium
In a patient with a high clinical suspicion of pulmonary thromboembolism, which is the best investigation?
In a patient with a high clinical suspicion of pulmonary thromboembolism, which is the best investigation?
Show Hint
High suspicion needs a confirmatory test - CT pulmonary angiography, not D-dimer.
Updated On: Jun 24, 2026
- D-dimer
- CT angiography
- Catheter angiography
- Colour Doppler
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: With a strong clinical suspicion of PE, the diagnostic algorithm moves straight to confirmatory imaging rather than to D-dimer, because a screening test cannot safely exclude disease in a high-probability patient.
Step 2: The modern workhorse is CT pulmonary angiography. Multidetector CT lets the whole lung be scanned in a single breath-hold, giving sub-millimetre resolution that exceeds invasive angiography and reveals even small peripheral emboli.
Step 3: Beyond confirming the clot, CT shows the right and left ventricles, so right ventricular enlargement can flag patients at far higher 30-day mortality. This dual diagnostic and prognostic value makes it the preferred first-line test.
Step 4: By comparison, catheter angiography is invasive and now reserved for special cases, colour Doppler evaluates deep leg veins rather than the pulmonary tree, and D-dimer only screens low-risk patients. CT angiography wins.
\[\boxed{\text{CT angiography (CT pulmonary angiography)}}\]
Step 2: The modern workhorse is CT pulmonary angiography. Multidetector CT lets the whole lung be scanned in a single breath-hold, giving sub-millimetre resolution that exceeds invasive angiography and reveals even small peripheral emboli.
Step 3: Beyond confirming the clot, CT shows the right and left ventricles, so right ventricular enlargement can flag patients at far higher 30-day mortality. This dual diagnostic and prognostic value makes it the preferred first-line test.
Step 4: By comparison, catheter angiography is invasive and now reserved for special cases, colour Doppler evaluates deep leg veins rather than the pulmonary tree, and D-dimer only screens low-risk patients. CT angiography wins.
\[\boxed{\text{CT angiography (CT pulmonary angiography)}}\]
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