Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The mediastinal and hilar contours are unchanged . Mild pulmonary vascular congestion is new in the interval . Retrocardiac opacification may reflect atelectasis though infection or aspiration can not be excluded . Patchy right basilar opacity may also reflect atelectasis . A trace left pleural effusion also appears new in the interval . No pneumothorax is identified . Clips from prior cholecystectomy are seen in the right upper quadrant of the abdomen . No acute osseous abnormality is visualized .
    OUTPUT:
    
Mild pulmonary vascular congestion and new retrocardiac opacity , potentially atelectasis though infection or aspiration are not excluded . Small left pleural effusion , also new in the interval .