Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Heart size is appears mildly enlarged but similar . The mediastinal and hilar contours are unchanged . There is mild pulmonary vascular congestion with a small left pleural effusion , perhaps increased in the interval . Patchy opacity in the retrocardiac region may reflect atelectasis , though infection is not excluded in the correct clinical setting . No pneumothorax is identified . No acute osseous abnormality is visualized .
    OUTPUT:
    
Low lung volumes . Mild pulmonary vascular congestion . Small left pleural effusion , perhaps minimally increased in the interval , with left basilar opacity , likely atelectasis . Infection , however , is not excluded in the correct clinical setting .