Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A central venous catheter again terminates at the cavoatrial junction . The cardiac , mediastinal and hilar contours appear stable . Increased density at the left lung base probably reflects atelectasis . Very mild fluid overload is suspected . It is difficult to exclude trace pleural effusions .
    OUTPUT:
    
Developing opacity at the left lung base , probably in the lingula . This may be due to minor atelectasis but developing infection is not excluded by this examination and the possibility should be correlated with clinical circumstances .