Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate to large right pneumothorax is demonstrated without evidence of leftward shift of mediastinal structures to suggest tension . There is atelectasis of the right lung . Left lung is clear . Pulmonary vasculature is normal . Heart size is top normal . Mediastinal and hilar contours are unremarkable . No pleural effusion is demonstrated . No acute osseous abnormality is identified .
    OUTPUT:
    
Moderate to large right pneumothorax without evidence of tension , similar in size compared to the previous exam .