Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal with mild tortuosity of the thoracic aorta . Hilar contours are unremarkable . Lungs are clear . Most pleural surfaces are normal except for posterior thickening probably due to healed left posterolateral rib fractures . Midthoracic disc space narrowing is due to chronic disc degeneration .
    OUTPUT:
    
No acute cardiopulmonary abnormality .