Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is mildly enlarged but unchanged . The mediastinal and hilar contours are unremarkable . The pulmonary vasculature is not engorged . There is minimal atelectasis in the lung bases . No focal consolidation , pleural effusion or pneumothorax is seen . Multilevel degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
Mild bibasilar atelectasis . No pneumothorax .