Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs when compared to the prior study demonstrated marked improvement in the right pleural effusion with unchanged small left pleural effusion . No pneumothorax is seen . Otherwise , the lungs are clear , and the cardiac and mediastinal contours are unchanged .
    OUTPUT:
    
Status post thoracentesis for right pleural effusion with no evidence of pneumothorax . Unchanged left pleural effusion .