Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate a moderate - sized right apical pneumothorax with rightward shift of the mediastinum , which is likely due to prior surgery . There is substantial collapse of the remaining right lung with minimal pulmonic gas seen in the right lung field . Left lung is essentially clear . Heart size is normal .
    OUTPUT:
    
Moderate right apical pneumothorax , with rightward shift of the mediastinum and substantial collapse of the remaining right lung , with only minimal aeration seen .