Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A moderate to large right pneumothorax is present with atelectasis of the right lung and slight leftward shift of mediastinal structures . Heart size is normal . Mediastinal and hilar contours are unremarkable . No pulmonary edema is present . Left lung is clear . No pleural effusion is present . No acute osseous abnormality is present .
    OUTPUT:
    
Moderate to large right pneumothorax with mild leftward shift of mediastinal structures concerning for an element of tension .