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
Contrast used for MRI: September 2012, March 2013 (f, g) 
Select and explain. 
A. Iodine, B. Gadolinium, C. Metrazamide, D. Omnipaque
B: Gadolinium
Answer: B: Gadolinium 
Explanation: Ans. B i.e. Gadolinium MRI MC contrast agent used in MRI: Gadolinium DTPA C/I to MRI: - Cardiac pacemakers, - Aneurysmal clips etc. Faradays cage: MRI rooms are shielded by continuous sheets of copper or aluminium from interference by external electromagnetic radiation.