Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Interval development of white out of the right hemithorax is likely due to a large right pleural effusion which is increased substantially since the prior study . The heart size is difficult to assess given the presence of the large right pleural effusion . No pulmonary vascular congestion is seen . The left lung is clear without pleural effusion or pneumothorax . No acute osseous abnormality is present . Mild leftward shift of mediastinal structures is noted .
    OUTPUT:
    
Large right pleural effusion has increased substantially now resulting in white out of the right hemithorax .