Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to the chest radiographs obtained 2 days prior , the diffuse , bilateral parenchymal opacities have increased in extent and severity , but with persistent peripheral sparing . Increased dilatation of the azygos vein . Small , bilateral pleural effusions . Mild cardiomegaly is unchanged . No pneumothorax .
    OUTPUT:
    
Bilateral parenchymal opacities are more consistent with severe pulmonary edema than multifocal pneumonia , but can not exclude a concurrent infectious process .