Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the prior study , there is no significant change in the moderate left pleural effusion on for differences in positioning . Retrocardiac opacity likely reflects a combination of the effusion and atelectasis although superimposed infection is also possible in the correct clinical setting . Stable heart size and mediastinal contours . Right lung is clear .
    OUTPUT:
    
Stable appearance of the chest with moderate left pleural effusion and retrocardiac atelectasis and / or consolidation .