Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post previous median sternotomy and coronary artery bypass surgery . Low lung volumes accentuate the cardiac silhouette and bronchovascular structures . An area of poorly defined opacity is present in the left infrahilar region with an adjacent linear area of atelectasis . Right lung is grossly clear . No definite pleural effusion . Mild elevation of left hemidiaphragm .
    OUTPUT:
    
Nonspecific left infrahilar opacity , which may represent atelectasis or a developing pneumonia given the clinical suspicion for this entity .