Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the prior study there has been interval increase in bilateral lower lung opacities . Diffuse bilateral interstitial lung disease is unchanged . The heart is normal and there is no vascular congestion , pleural effusion or pneumothorax . The bones and soft tissues are unremarkable .
    OUTPUT:
    
Interval increase in bilateral lower lung opacities could represent atelectasis , effusion , or pneumonia in the appropriate clinical setting .