Comparison of chest computed tomography features in the acute phase of cardiogenic pulmonary edema and acute respiratory distress syndrome on arrival at the emergency department.

PURPOSE: Discriminating cardiogenic pulmonary edema (CPE) from acute respiratory distress syndrome (ARDS) is a serious problem in emergency departments, and the ability of chest radiographs to differentiate between these 2 entities is limited. We compared the chest computed tomography (CT) findings in the acute phase of CPE with those of ARDS.

MATERIALS AND METHODS: Outpatients with acute respiratory failure presenting to emergency departments with bilateral pulmonary opacities were enrolled. The patients included not only those who visited our hospital first but also those referred from other hospitals. Two intensivists who were blinded to the results of the chest imaging studies reviewed the patients' clinical records independently in order to determine a diagnosis of CPE or ARDS, and the chest CT findings were independently evaluated by 2 radiologists who were unaware of the patients' clinical information. The positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the statistically different findings were calculated using standard definitions.

RESULTS: Forty-one patients with CPE and 20 patients with ARDS were assessed. Upper-lobe-predominant ground-glass attenuation, central-predominant ground-glass attenuation, and central airspace consolidation were associated with high PPVs (95.2%, 92.3%, and 92.0%, respectively) and moderate NPVs (47.5%, 51.4%, and 50.0%, respectively) to diagnose as CPE. Left-dominant pleural effusion and small ill-defined opacities revealed relatively high PPVs (71.4% and 58.3%, respectively) and NPVs (72.2% and 73.5%, respectively) to diagnose as ARDS. The overall accuracy of the diagnosis by chest CT was 88.5% (54/61).

CONCLUSIONS: Chest CT may be a useful tool for differentiating CPE from ARDS in the emergency department setting.