Chest X-ray Findings Indicative of Pulmonary Embolism
Chest X-ray findings in pulmonary embolism are often non-specific, with the most reliable findings being pleural-based opacity (Hampton's hump), decreased pulmonary vascularity (Westermark sign), and amputation of the hilar artery. 1
Common Chest X-ray Findings in PE
Normal chest X-ray: Present in up to 12% of patients with confirmed PE, a normal chest X-ray in a hypoxic, breathless patient should increase suspicion for PE 2
Pleural-based wedge-shaped opacity (Hampton's hump): Present in 23% of PE cases, representing pulmonary infarction 1
Decreased pulmonary vascularity (Westermark sign): Found in 36% of PE cases, indicating reduced blood flow to affected areas 1
Amputation of hilar artery: A more specific sign present in 36% of PE cases but only 1% of non-PE cases 1
Pleural effusion: Present in 46% of PE cases (compared to 33% in non-PE cases) 1
Atelectasis or infiltrate: Found in 49% of PE cases but also common (45%) in non-PE cases 1
Elevated diaphragm: Present in 36% of PE cases versus 25% in non-PE cases 1
Diagnostic Value of Chest X-ray in PE
Chest X-ray is rarely diagnostic for PE but is valuable for excluding other causes of dyspnea and chest pain such as pneumonia, pneumothorax, heart failure, or tumor 1
The main utility of chest X-ray is to aid in the interpretation of ventilation-perfusion scans, as abnormalities on chest X-ray can affect V/Q scan interpretation 1, 2
A normal chest X-ray in a patient with acute dyspnea, hypoxemia, and risk factors should increase clinical suspicion for PE 1
Clinical Context for Interpreting Chest X-ray Findings
Chest X-ray findings should always be correlated with clinical symptoms and risk factors for PE 1
Common symptoms of PE include dyspnea (80%), pleuritic chest pain (52%), cough (20%), hemoptysis (11%), and syncope (19%) 1
Tachypnea (70%) and tachycardia (26%) are common signs in patients with PE 1
Limitations of Chest X-ray in PE Diagnosis
No single chest X-ray finding is sufficiently sensitive or specific to confirm or exclude PE 2
Classic radiographic signs (Hampton's hump, Westermark sign) are relatively uncommon and easily missed 2, 3
Additional imaging (CT pulmonary angiography or V/Q scan) is always required to confirm the diagnosis 1
Advanced Imaging Recommendations
CT pulmonary angiography is now the primary imaging modality for evaluating suspected PE 1
V/Q scanning remains useful when CT is contraindicated or unavailable 1
Chest X-ray should be considered an initial screening tool, not a definitive test for PE 1
Remember that while chest X-ray findings can raise suspicion for PE, they are neither sensitive nor specific enough to confirm or exclude the diagnosis. The primary value of chest X-ray in suspected PE is to rule out alternative diagnoses and provide context for interpreting other imaging studies.