Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The aorta is mildly unfolded . The mediastinal and hilar contours are otherwise unremarkable . Except for minimal atelectasis in the retrocardiac region , the lungs are essentially clear . No pleural effusion or pneumothorax is present . Mild degenerative changes are noted in the thoracic spine . No displaced fractures are visualized .
    OUTPUT:
    
No acute cardiopulmonary abnormality .