Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volume is low . Mild left lower lobe opacity is likely atelectasis . There is no pneumothorax or pleural effusion . Cardiomediastinal silhouette is normal size . Pulmonary vascular congestion is mild .
    OUTPUT:
    
No pneumothorax . Mild pulmonary vascular congestion .