Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours are unremarkable . Heart size is normal . Mild atherosclerotic calcifications are seen within the aortic knob . The lungs are clear and the pulmonary vasculature is normal . No pleural effusion or pneumothorax is present . There are mild degenerative changes within the imaged lumbar spine .
    OUTPUT:
    
No acute cardiopulmonary abnormality .