A 55-year-old man presents with sudden onset pleuritic chest pain and dyspnea 10 days after total knee replacement surgery. He has tachycardia (110/min), tachypnea (24/min), and SpO2 91% on room air. D-dimer is elevated at 1800 ng/mL. Which is the most appropriate next investigation to confirm the suspected diagnosis?

• A Ventilation-perfusion (V/Q) scan
• B Echocardiography
• C Doppler ultrasound of lower limbs
• D CT pulmonary angiography (CTPA) ✓

Explanation

In a post-surgical patient with intermediate-high clinical probability of pulmonary embolism and elevated B-dimer, CTPA is the investigation of choice for confirming PE. It directly visualizes thrombus in pulmonary arteries with high sensitivity and specificity. V/Q scan is reserved for patients with renal failure or contrast allergy. Lower limb Doppler detects DVT but does not confirm PE.

Reference: Davidson's Principles and Practice of Medicine, 24th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.