Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Left lower lobe retrocardiac opacity may represent postsurgical changes . Left fissural fluid or subsegmental atelectasis is mild . Right costophrenic angle atelectasis is mild . No pleural effusion . Small left apical pneumothorax . Left chest tube ends in the posterior superior right lower lobe .
    OUTPUT:
    
1 . Small left apical pneumothorax . 2 . No effusion .