What are the signs on a chest X-ray (CXR) for pulmonary embolism (PE)?

Chest X-ray Findings in Pulmonary Embolism

Chest X-ray is rarely diagnostic for PE but is essential for excluding other causes of dyspnea and chest pain such as pneumonia, pneumothorax, or heart failure. 1, 2

Common Radiographic Findings

The chest X-ray is abnormal in approximately 88% of patients with PE, though most findings are non-specific: 3

Classic Signs (Low Sensitivity but Higher Specificity)

• Hampton's hump (pleural-based wedge-shaped opacity representing pulmonary infarction) is present in 23% of PE cases 2, 3
• Westermark sign (decreased pulmonary vascularity/oligemia in affected areas) is found in 36% of PE cases 2, 3, 4
• Fleischner sign (amputation or enlargement of hilar artery) is present in 36% of PE cases but only 1% of non-PE cases, making it more specific 2

Non-Specific Findings (Common but Poor Predictors)

• Atelectasis or parenchymal infiltrate is the most common finding at 49% of PE cases, but also present in 45% of non-PE cases 2, 3
• Pleural effusion occurs in 46% of PE cases (versus 33% in non-PE cases), frequently hemorrhagic 1, 2, 5
• Elevated hemidiaphragm is present in 36% of PE cases versus 25% in non-PE cases 1, 2

Clinical Utility and Limitations

The primary value of chest X-ray is to exclude alternative diagnoses that mimic PE clinically, not to confirm PE. 1, 3

Key Clinical Points

• A normal chest X-ray occurs in only 12% of patients with confirmed PE 3
• When a patient presents with acute dyspnea, hypoxemia, and risk factors but has a normal chest X-ray, this should increase clinical suspicion for PE 2
• Chest X-ray findings must be correlated with clinical symptoms: dyspnea (80%), pleuritic chest pain (52%), tachypnea (70%), and tachycardia (26%) 1, 2

Diagnostic Algorithm

CT pulmonary angiography (CTPA) is now the recommended initial lung imaging modality for suspected PE regardless of chest X-ray findings. 1, 2

• Chest X-ray should be obtained to exclude pneumonia, pneumothorax, heart failure, or other alternative diagnoses 1, 2
• Do not rely on chest X-ray alone to diagnose or exclude PE—additional imaging is always required for confirmation 2
• CTPA will definitively identify intravascular thrombus, wedge-shaped opacities from infarction, right ventricular strain patterns, and alternative diagnoses 2

Common Pitfalls to Avoid

• Never exclude PE based on a normal or non-specific chest X-ray—up to 88% of PE patients have abnormal radiographs, but findings overlap significantly with other conditions 3
• Do not delay CTPA waiting for chest X-ray results in hemodynamically unstable patients—imaging should occur within 1 hour for massive PE 2
• The presence of atelectasis, infiltrate, or pleural effusion on chest X-ray does not exclude PE and should not prevent further diagnostic workup if clinical suspicion remains 2, 3
• Chest radiography has poor sensitivity for early airway abnormalities and ground-glass opacities—a normal chest X-ray does not exclude significant pulmonary pathology 2

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