Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right - sided catheter has been placed . The previously seen right pleural effusion has decreased in size . A small residual pleural effusion is likely present . There is also mild minimal atelectasis at the right lung base . No obvious pneumothorax is detected . The cardiomediastinal silhouette is unchanged . Mild vascular plethora and previously seen retrocardiac opacity are improved . Minimal blunting of the left costophrenic angle noted , without gross effusion .
    OUTPUT:
    
Interval placement of right - sided catheter with decrease in size of the previously seen right pleural effusion . Underlying atelectasis noted . No obvious pneumothorax . Possibility of a small occult pneumothorax is not entirely excluded . Interval improvement in vascular plethora and retrocardiac opacity .