Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a left - sided pleural effusion with retrocardiac opacity that either represents pneumonia or atelectasis . Mild right basilar atelectasis . Small right pleural effusion . There is no pulmonary vascular congestion . There is mild cardiomegaly . The upper lung zones are clear .
    OUTPUT:
    
1 . Left pleural effusion with retrocardiac opacity either representing atelectasis or pneumonia . Small right pleural effusion with adjacent atelectasis . 2 . Mild cardiomegaly . No pulmonary vascular congestion .