Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post coronary artery bypass graft surgery . There is patchy opacity at the left lung base with new elevation of the left hemidiaphragm , moderate in degree , suggesting coinciding volume loss . Otherwise , the lungs appear clear . There is no definite pleural effusion although it would be difficult to detect a subpulmonic pleural effusion on the left .
    OUTPUT:
    
New opacity with volume loss at the left lung base which can probably be attributed to atelectasis although pneumonia is not excluded . Short - term follow - up radiographs with PA and lateral technique may be helpful to reassess .