Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low with mild bibasilar atelectasis . The lungs are otherwise clear . There is no pleural effusion or pneumothorax . Cardiomediastinal silhouette is unremarkable . There is heavy calcification of the aortic knob .
    OUTPUT:
    
No acute cardiopulmonary abnormality