Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes with bibasilar subsegmental atelectasis . Pneumonia in these regions can not be completely excluded . The cardiac silhouette is mildly enlarged , which is chronic . There is no pneumothorax . Pulmonary vascularity is normal .
    OUTPUT:
    
Chronic bibasilar subsegmental atelectasis . Pneumonia in these regions can not be fully excluded .