Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours are unremarkable . The heart size is within normal limits . Lungs are clear and the pulmonary vasculature is normal . No pneumothorax or pleural effusion is present . There are mild degenerative changes in the thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary abnormality .