Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . Cardiac silhouette is top normal in size . There is no pleural effusion , pneumothorax or evidence of overt pulmonary edema , however the azygos vein is noted to be large .
    OUTPUT:
    
No evidence of pneumonia . Slight volume overload evidenced by enlarged azygos vein .