Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Scarring projecting within the left mid lung zone is unchanged though with improvement in scattered atelectasis and pleural fluid . There are no new focal recurring opacities concerning for pneumonia . There are no pleural effusions or pneumothorax . The cardiomediastinal and hilar contours are normal . The patient is status post median sternotomy for removal of thymoma . Pulmonary vascularity is not increased .
    OUTPUT:
    
Expected postoperative appearance after median sternotomy . No acute cardiopulmonary process .