Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest again mild demonstrate patchy opacification in the left lung base , which is likely atelectasis . There is no pleural effusion or pneumothorax . The cardiac and mediastinal contours are normal . Previously seen right sided PICC is no longer seen . Cholecystectomy clips are noted within the right upper quadrant .
    OUTPUT:
    
Patchy opacification left lung base may represent atelectasis , although , aspiration can not be excluded .