Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Even allowing for the projection , there is mild cardiomegaly . There is persistent left lower lobe atelectasis . Increased opacity at the right lung base is more conspicuous than on the prior study . Given the lack of associated volume loss , appearances are suspicious for superimposed infection . There is persistent prominence of the bilateral hila with mild pulmonary vascular congestion . No pneumothorax seen .
    OUTPUT:
    
Background changes of atelectasis and pulmonary vascular congestion . Increased opacity at the right lung base suspicious for superimposed infection .