Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are not significantly changed and are within normal limits . Again seen is a large right pleural effusion , not significantly changed in size from the prior study . There is adjacent atelectasis at the right base . New , subtle retrocardiac opacity is likely representative of atelectasis . There is no evidence of pneumothorax .
    OUTPUT:
    
1 . Large right pleural effusion and adjacent right basal atelectasis is not significantly changed from the prior study . Superimposed infection can not be excluded . 2 . New , subtle left retrocardiac opacity is likely representative of atelectasis .