Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right - sided hemodialysis catheter in - situ with the tip at the cavoatrial junction . Mild interval decrease in heart size . Opacification in medial bilateral lower lung zones appears slightly more prominent and may represent atelectasis or pneumonia . Small residual effusions bilateral .
    OUTPUT:
    
Mild interval progression of the airspace opacification in the medial aspects of the lower lung zones bilateral may represent atelectasis or pneumonia .