Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since the prior examination , there has been marked interval improvement of previously large left pleural effusion that is now small in extent . There is a small right pleural effusion . There is left basilar opacification , likely atelectasis . There are no new focal occurring opacities concerning for pneumonia . There is no evidence of pneumothorax . The cardiomediastinal and hilar contours demonstrate moderate cardiomegaly and are otherwise unremarkable .
    OUTPUT:
    
Interval improvement of a previously large left pleural effusion , now small in extent . No evidence of pneumothorax .