Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . There are persistent small bilateral pleural effusions , left greater than right . Compared to prior study , the bibasilar opacities have improved , likely atelectasis in postoperative setting . Heart size is mildly enlarged . Median sternotomy wires and mitral valve annuloplasty ring are in appropriate positions .
    OUTPUT:
    
Improving bibasilar atelectasis . No new areas of consolidation to suggest a new source of infection .