Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low . The cardiac , mediastinal and hilar contours appear unchanged . The heart is at the upper limits of normal size . There is a similar infrahilar opacification suggesting atelectasis or scarring . More generally there is increased bibasilar opacification , but streaky and band - like in morphology , mostly suggestive of atelectasis or scarring with a suspected small left - sided pleural effusion .
    OUTPUT:
    
Bibasilar opacification , increased but non-specific . Pneumonia is a consideration but the appearance could be compatible with atelectasis . Correlation with a CT performed earlier on the same day is also more concordant with a noninfectious explanation , however .