FINDINGS:
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.

IMPRESSION:
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.