Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a large right - sided pneumothorax resulting in greater than ___ of right lung collapse . No pneumothorax on the left . There is no substantial pleural effusion . Generalized opacification of the left hemithorax likely represents a component of atelectasis due to leftward mediastinal shift . However , underlying chronic lung disease can not be excluded . Heart size is normal . No acute osseous abnormalities identified .
    OUTPUT:
    
Right - sided tension pneumothorax .