Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post sternotomy . A Port - A - Cath terminates at the cavoatrial junction . The heart is at the upper limits of normal size . A calcified lymph node is seen along the aortopulmonary window . The cardiac , mediastinal and hilar contours do not appear significantly changed . The lung volumes are low . There is persistent patchy opacification in the left lower lobe , which appears somewhat more dense and compressed , perhaps coinciding with differences in lung volumes rather than a true interval change however . In fact , left basilar opacities are more similar to ___ , where lungs volumes were somewhat lower than on the more recent prior examination . There is no pleural effusion or pneumothorax . Bony structures are unremarkable .
    OUTPUT:
    
Persistent left basilar opacification , suspected to represent primarily atelectasis . However , the possibility of superimposed pneumonia could be considered in the appropriate clinical setting versus increased atelectasis associated with low lung volumes .