Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Overall , aeration of the lung bases appears improved compared to recent prior examination . There is still a residual moderate left pleural effusion and probable trace right pleural effusion . Atelectasis is presumed on the left . A rounded opacity within the right lung base likely represents focal atelectasis , though followup radiographs are recommended to confirm resolution . There is no overt pulmonary edema . Mediastinal and hilar contours appear within normal limits . Evaluation of the cardiac silhouette is limited secondary to the bibasal opacities . A prosthetic aortic valve is in expected position . Median sternotomy wires appear intact . There is no pneumothorax .
    OUTPUT:
    
1 . Improved aeration of the lung bases , though with persistent bilateral pleural effusions , moderate on the left and small on the right . 2 . Ill - defined right basilar opacity may reflect residual atelectasis , though followup radiographs are recommended as developing infection remains in the differential .