This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'Increased radiolucency of one sided hemithorax may be caused by all except \nSelect and explain. \nA. Obstructive Emphysema, B. Pneumothorax, C. Expiratory film, D. Patient rotation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Expiratory film How can a normal expiratory film leads to increased radiolucency of hemithorax? So the answer is very obvious. Ted Radiolucency of one side means there is U/L lung pathology. Obst. Emphysema & U/L Pneumothorax may lead to U/L lung collapse & radiolucency. Patient rotation may also lead to false impression of U/L radiolucency. But expiration film in normal conditions may never be a cause of this. Causes of U/L Radiolucent Hemithorax * Always remember that decreased 11/L lung mass as in pulmonary agenesis pulmonary hypoplasia, collapse & pneumonectomy are the causes of U/L radiodense hemithorax with I/L mediastinal displacement.', 'role': 'assistant'}]