Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . Aortic knob calcifications are present . Mediastinal and hilar contours are normal . Pulmonary vasculature is normal . Minimal atelectasis is noted in the retrocardiac region . Lungs are otherwise clear . No focal consolidation , pleural effusion or pneumothorax is seen . Mild to moderate degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary abnormality .