This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Obstetrics And Gynaecology, Subject name: Radiology
[{'content': 'Safest radiological investigation in pregnancy is- \nSelect and explain. \nA. CT, B. MRI, C. X-ray, D. HRCT', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans is \'b\' i.e. MRI * "The American college of radiology (ACR) advices that pregnant patients can undergo MRI without risks for the fetus" - MRI of fetal and maternal diseases in pregnancy; p 439Other advantaged and disadvantages of MRIAdvantagesDisadvantages* Static and cine or movie images* Multiple plane images* Good contrast* No known health hazard* No ionizing radiation* Excellent soft tissue differentiation* Good for soft tissue injuries of knee, ankle, shoulder* Better than CT in visualizing vascular structures* More expensive than CT* Long scan time may result in motion artifacts* Limited availability* Not good for calcified lesions and bone (CT is better)', 'role': 'assistant'}]