Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . There is again an abnormal contour to the prevascular window reflecting known lymphadenopathy . There is no pleural effusion or pneumothorax . The lungs appear clear . The patient is status post aortic valve replacement .
    OUTPUT:
    
Mediastinal lymphadenopathy . No evidence of acute cardiopulmonary disease .