Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . The cardiomediastinal silhouette is stable . The pulmonary vasculature is unremarkable . Left basilar opacity is unchanged since prior examination . No definite pleural effusion or pneumothorax .
    OUTPUT:
    
1 . No evidence of pulmonary edema . 2 . Persistent left basilar opacity , which may represent atelectasis .