Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a pigtail catheter seen at the right lung base , which appears unchanged in comparison to the prior chest radiograph . Low lung volumes . There is bibasilar patchy opacification , right worse than left . There is an unchanged small right pneumothorax . Heart size is stable . The mediastinal and hilar contours are stable . The pulmonary vasculature is normal . No pleural effusion . There are no acute osseous abnormalities .
    OUTPUT:
    
1 . Pigtail catheter in appropriate positioning . 2 . Unchanged small right apical pneumothorax . 3 . Low lung volumes and bibasilar patchy opacities , which likely reflect atelectasis .