This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CT SCAN, Subject name: Radiology
[{'content': 'Which of the following modality is most sensitive investigation for pneumothorax? \nSelect and explain. \nA. USG, B. CT, C. X-ray, D. MRI', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pneumothorax: Refers to the presence of gas (air) in the pleural space. When this collection of gas is constantly enlarging with resulting compression of mediastinal structures, it can be life-threatening and is known as a tension pneumothorax. Provided lung windows are examined, a pneumothorax is very easily identified on CT, and should pose essentially no diagnostic difficulty. - IOC- CT Scan - Best X-ray view- Expiratory Films', 'role': 'assistant'}]