Relation of plain chest radiographic findings to pulmonary arterial pressure and arterial blood oxygen levels in patients with acute pulmonary embolism.

Abnormalities of the plain chest radiograph of 123 patients with acute pulmonary embolism (PE) and no prior cardiac or pulmonary disease were related to the pulmonary arterial mean pressure, the partial pressure of oxygen in arterial blood, and the alveolar-arterial oxygen gradient. Patients with either a prominent central pulmonary artery or cardiomegaly had higher pulmonary arterial mean pressures than did patients with atelectasis, a pulmonary parenchymal abnormality or pleural effusion (p less than 0.001). These radiographic findings give clues to the severity of pulmonary hypertension in acute PE and suggest that pulmonary infarction or hemorrhage is associated with less severe PE.