Pulmonary embolism chest x ray

The majority of chest X-rays (CXR) of patients with pulmonary embolism (PE) are abnormal; however, CXR findings are of limited value to establish a diagnosis of a pulmonary embolus (PE).^[1] The importance of a CXR obtained in patients with shortness of breath or chest pain suspected to have a PE is to rule out alternative diagnoses such as pneumonia, congestive heart failure, and rib fracture.^[2] The most common findings reported among patients with PE include atelectasis and/or increased opacity in parenchymal areas^[3] and cardiomegaly.^[4]

• According to a substudy of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study on 1063 patients suspected to have PE, the most common CXR finding among patients with PE was atelectasis and/or increased opacity in parenchymal areas.^[3] There was no significant difference between the prevalence of atelectasis and/or increased opacity in parenchymal areas among patients with confirmed PE vs those without PE.^[3]

• In contrast, in the observational retrospective International Cooperative Pulmonary Embolism Registry (ICOPER) study conducted at 52 hospitals in seven countries and involving 2,454 patients with suspected PE, cardiomegaly was the most common chest radiographic abnormality associated with acute PE. Cardiomegaly was not associated with the echocardiographic findings of hypokinesia.^[4]

• Approximately 12%-24% of patients with PE have a normal CXR.^[3][4]

• “Classic”, yet less uncommon, findings of PE on CXR include:
  • Westermark sign: vasoconstriction distal to the pulmonary embolus
  • Hampton hump: peripheral wedge-shaped density above the diaphragm
  • Palla’s sign: enlarged right descending pulmonary artery

• PE-related CXR changes have been evaluated among subjects free of cardiac and pulmonary diseases who were suspected to have PE and were enrolled in the PIOPED study. The CXR findings were compared between 117 patients with confirmed PE vs 247 patients without PE. The most common CXR abnormality in PE was atelectasis and/or increased opacity in parenchymal areas. Shown below are the percentage of CXR findings among patients with PE vs those without PE:^[5]
  • Atelectasis and/or increased opacity in parenchymal areas: 68% vs 48% ( p <0.001)
  • Pleural effusion: 48% vs 31% (p <0.01)
  • Elevated diaphragm: 24% vs 19% (p-value is non-significant)
  • Prominent central pulmonary artery (or Fleischner sign): 15% vs 11% (p-value is non-significant)
  • Cardiomegaly: 12% vs 11% (p-value is non-significant)
  • Westermark’s sign: 7% vs 2% (p-value is non-significant)
  • Pulmonary edema: 4% vs 13% (p <0.05)

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