This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamentals in Radiology, Subject name: Radiology
[{'content': '"Time of flight" technique is employed in - \nSelect and explain. \nA. Spiral CT, B. MR imaging, C. CT angiography, D. Digital radiography', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Time of flight angiography (TOF) is an MRI technique to visualize flow within vessels, without the need to administer contrast', 'role': 'assistant'}]