Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . No definite pneumonia or CHF . There is posterior blunting / pleural thickening on both sides accounting for some of the increased density in the retrocardiac region . Allowing for differences in rotation appearances are similar to the prior study from ___ and ___ . .
    OUTPUT:
    
No pneumonia . No significant change .