Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post coronary artery bypass graft surgery . The heart is normal in size . Mediastinal and hilar contours appear unchanged . The chest is hyperinflated . There is a new confluent posterior opacity in the left lower lobe with a bulging contour anteriorly . This appearance is not entirely specific but is suggestive of a pleural effusion , potentially with loculation as a part of it . However , other etiologies including confluent consolidation with pleural effusion or even potentially malignancy are not excluded by this examination . A thick flowing anterior osteophyte is unchanged along the thoracic spine .
    OUTPUT:
    
Pleural - based left lower lobe opacity with a bulging anterior contour . Differential considerations include a pleural effusion with large loculated component , versus consolidation with a bulging contour and pleural effusion ( which could be seen with some infections , for example , Klebsiella pneumonia ) , although even malignancy is not excluded . Follow - up radiographs are recommended to show resolution versus consideration of chest CT if the likely etiology is not very clear at clinical grounds .