Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to the prior radiograph , a single semi-erect portable view of the chest demonstrates significantly lower lung volumes . Bibasilar opacities are most consistent with atelectasis , although in the correct clinical setting , pneumonia could certainly be considered . There are possible small bilateral pleural effusions . Patient is status post median sternotomy and CABG . Cardiac size is exaggerated by the AP view as well as the lower lung volumes but given these appears relatively stable . Crowding of the bronchovascular structures is present , with possible mild pulmonary vascular congestion . No pneumothorax . Heterotopic ossification is again noted along the inferior margin of the right glenoid .
    OUTPUT:
    
Low lung volumes accentuating both pulmonary vasculature as well as bibasilar atelectasis . Underlying pneumonia is certainly a possibility in the correct clinical setting . Possible small bilateral pleural effusions .