This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Magnetic Resonance Imaging, Subject name: Radiology
[{'content': 'A 40 year old male patient on long term steroid therapy for systemic disease, presents with recent onset of severe pain in the right hip. Imaging modality of choice for this problem is- \nSelect and explain. \nA. CT scan, B. Bone scan, C. MRI, D. Plain X-ray', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Long term steroid therapy for systemic disease + severe pain in the right hip = AVASCULAR NECROSIS IOC for Avascular Necrosis: MRI Snow cap sign on plain radiograph: AVN of humerus or femur head Figure: snow cap sign due to AVN of humerus head', 'role': 'assistant'}]