Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . The previously seen lucency is caused by platelike atelectasis immediately superior to the diaphragm . Otherwise , the lungs are grossly clear . No pleural effusion or pneumothorax . No pneumoperitoneum . Hilar contours are normal . The aorta is tortuous .
    OUTPUT:
    
No pneumoperitoneum . Platelike atelectasis at the left lung base is unchanged from the prior examination on the same date .