Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild enlargement of the left atrium appears similar when compared to the prior study . Remainder of the cardiac silhouette is unchanged . The mediastinal and hilar contours are normal . Lungs are clear and the pulmonary vascularity is normal . No pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities . Minimal degenerative changes are seen within the lower thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary abnormality .