FINDINGS:
Blunting of the left costophrenic angle may reflect focal atelectasis or trace
 pleural fluid.  Left retrocardiac airspace opacity appears slightly more
 conspicuous compare to prior.  The upper lung fields are clear bilaterally. 
 There is no right pleural effusion, pneumothorax, or frank pulmonary edema. 
 The heart remains mildly enlarged.  The descending thoracic aorta is ectatic,
 and calcifications are seen at the aortic arch.  Multilevel degenerative
 changes are noted throughout the visualized thoracic spine.

IMPRESSION:
Mild cardiomegaly and probable trace left pleural effusion.  No overt
 interstitial pulmonary edema.  Left retrocardiac airspace opacity may reflect
 atelectasis, although superimposed infection is not excluded.