Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison with chest radiographs from ___ , there is increase in apparent opacity at the left lung base , which could reflect worsening infarct , infection or atelectasis . Lung volumes remain low . No large pleural effusion . No pneumothorax . No central vascular congestion or overt pulmonary edema . Mediastinal and hilar contours are stable . Heart size is normal .
    OUTPUT:
    
Slight interval increase in opacity at the left lung base , which could represent worsening infarct , infection or atelectasis .