Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since ___ , previously moderate bibasilar and retrocardiac atelectasis is minimally improved , and small to moderate bilateral pleural effusions , left greater than right , are unchanged . Lung volumes remain low . Moderate cardiomegaly is unchanged . No pneumothorax or pulmonary edema .
    OUTPUT:
    
Previously moderate bibasilar retrocardiac atelectasis is minimally improved , and small to moderate bilateral pleural effusions , left greater than right , are unchanged since ___ .