Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal with mild tortuosity of the aorta . Left heart contour is prominent , with adjacent lucency . Hilar contours are normal . Few scattered densities are punctate , either representing vasculature en face or punctate granuloma . Lungs are otherwise clear . Pleural surfaces are clear without effusion or pneumothorax .
    OUTPUT:
    
1 . Possible pneumomediastinum . If there is clinical suspicion , this can be further characterized by CT . 2 . No pneumonia .