Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . The aorta remains markedly tortuous with calcifications noted at the aortic knob . The pulmonary vasculature is normal . The hilar contours are unremarkable . Lungs are clear . No pleural effusion or pneumothorax is demonstrated . Degenerative changes with anterior osteophyte formation are seen within the lower thoracic spine .
    OUTPUT:
    
No acute cardiopulmonary abnormality .