Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest were acquired . As before , the patient is status post midline sternotomy and CABG . Marked elevation of the left hemidiaphragm is not significantly changed . Heterogeneous opacities in the right mid to lower lung have substantially decreased compared to the prior study from ___ , likely atelectasis . There is also volume loss at the left lung base . The heart size is difficult to assess but does not appear significantly changed . The mediastinal contours are not significantly changed . Multilevel degenerative changes of the thoracic spine are noted . There is redemonstration of a mitral valve annuloplasty . There may be small bilateral pleural effusions . The air - filled gastric bubble is identified in an appropriate retrocardiac position .
    OUTPUT:
    
1 . Decreased right mid-to - lower lung opacities , consistent with improving atelectasis . Unchanged volume loss at the left lung base . 2 . Marked left hemidiaphragm elevation , not significantly changed . 3 . Small bilateral pleural effusions , containing less than 200 ml of fluid .