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': 'Which one of the following imaging modalities is most sensitive for evaluation of extra-adrenal Pheochromocytoma – \nSelect and explain. \nA. Ultrasound, B. CT, C. MRI, D. MIBG scan', 'role': 'user'}, {'content': 'Answer: D \nExplanation: MIBG is taken up by catecholamine granules and is used mainly for localizing pheochromocytomas in the adrenal and in extra-adrenal sites and for the detection of metastasis.', 'role': 'assistant'}]