Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volume is low . Left lower lobe opacity is likely atelectasis . There is no pleural effusion or pneumothorax . Substantially enlarged cardiac silhouette is similar to before . There is pulmonary vascular congestion .
    OUTPUT:
    
Left lower lobe opacity is likely atelectasis . Pulmonary vascular congestion .