Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . The heart size is top normal . There has been interval opacification of the right upper lobe , likely resulting from post-obstructive atelectasis due to the presence of the right upper lobe mass . Small left pleural effusion appears slightly increased in size compared to the prior study . The right lung is grossly clear . There is no pneumothorax . No acute osseous abnormality is visualized , though mild degenerative changes of the thoracic spine are present .
    OUTPUT:
    
New opacification of the right upper lobe likely representing postobstructive collapse due to the presence of the right upper lobe lung mass . Small left pleural effusion appears slightly increased in size compared to the prior study .