Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate chronic cardiomegaly remains unchanged . There is minimal pulmonary vascular congestion but no frank pulmonary edema . There are low lung volumes . There is heterogeneous opacity of the left lung base with worsening obliteration of the pleural surface . Pleural fluid at the left lung base remains unchanged . Note is made of multiple bilateral healed rib fractures .
    OUTPUT:
    
Heterogeneous opacity at left lung base with worsening obliteration of the pleural surface , which could represent worsening atelectasis , aspiration or early developing pneumonia . Close followup is recommended .