This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Radiology
A 40 yr. old male patient on long-term steroid therapy for a systemic disease presents with recent onset of severe pain in the right hip. The imaging modality of choice for this problem is? 
Select and explain. 
A. MRI scan, B. CT scan, C. Bone scan, D. Plain X-ray
A: MRI scan
Answer: A: MRI scan 
Explanation: Ans. A. MRI scan* MRI is the preferred imaging modality in this case.* This is a case scenario of recent onset of severe hip pain with a history of long-term steroid therapy suggesting the diagnosis of AVN (avascular necrosis) hip. MRI is the investigation of choice for AVN hip.