Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . The cardiac and mediastinal silhouettes are stable . There is subtle increase in opacity of the left mid to lower lung which is decreased compared to ___ , but slightly more apparent compared to ___ , underlying infectious process not excluded . No pleural effusion or pneumothorax is seen . No overt pulmonary edema . Sutures again seen in the left mid lung region .
    OUTPUT:
    
Subtle opacity projecting over the left mid to lower lung could be due to a subtle pneumonia .