Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . There is a slight prominence of the main pulmonary artery contour of uncertain significance , perhaps artifactual . Otherwise , the mediastinal and hilar contours are unremarkable . The lungs appear clear . There are no pleural effusions or pneumothorax . Bony structures are unremarkable .
    OUTPUT:
    
Minimal prominence of the main pulmonary artery contour , but probably within normal limits ; otherwise unremarkable .