Chest radiographs in acute pulmonary embolism. Results from the International Cooperative Pulmonary Embolism Registry.

OBJECTIVES: To characterize chest radiographic interpretations in a large population of patients who have received a diagnosis of acute pulmonary embolism and to estimate the sensitivity and specificity of chest radiographic abnormalities for right ventricular hypokinesis that has been diagnosed by echocardiography.
DESIGN: A prospective observational study at 52 hospitals in seven countries. PATIENTS: A total of 2,454 consecutive patients who had received a diagnosis of acute pulmonary embolism between January 1995 and November 1996.
RESULTS: Chest radiographs were available for 2,322 patients (95%). The most common chest radiographic interpretations were cardiac enlargement (27%), normal (24%), pleural effusion (23%), elevated hemidiaphragm (20%), pulmonary artery enlargement (19%), atelectasis (18%), and parenchymal pulmonary infiltrates (17%). The results of chest radiographs were abnormal for 509 of 655 patients (78%) who had undergone a major surgical procedure within 2 months of the diagnosis of pulmonary embolism: normal results for chest radiograph often accompanied pulmonary embolism after genitourinary procedures (37%), orthopedic surgery (29%), or gynecologic surgery (28%), whereas they rarely accompanied pulmonary emboli associated with thoracic procedures (4%). Chest radiographs were interpreted to show cardiac enlargement for 149 of 309 patients with right ventricular hypokinesis that was detected by echocardiography (sensitivity, 0.48) and for 178 of 485 patients without right ventricular hypokinesis (specificity, 0.63). Chest radiographs were interpreted to show pulmonary artery enlargement for 118 of 309 patients with right ventricular hypokinesis (sensitivity, 0.38) and for 117 of 483 patients without right ventricular hypokinesis (specificity, 0.76).
CONCLUSIONS: Cardiomegaly is the most common chest radiographic abnormality associated with acute pulmonary embolism. Neither pulmonary artery enlargement nor cardiomegaly appears sensitive or specific for the echocardiographic finding of right ventricular hypokinesis, an important predictor of mortality associated with acute pulmonary embolism.