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: Surgery
[{'content': 'Which of the following is true regarding principle of MRCP? \nSelect and explain. \nA. Use of IV Gadolinium contrast agent is used to enhance the biliary radicals and the pancreatic duct, B. Contrast agent is instilled percutaneously into the biliary radicals first and then MRI done, C. Intraluminal dye is used to create the three dimensional view of the biliary radicals and the pancreatic duct, D. Use of heavily T2 weighted images without contrast', 'role': 'user'}, {'content': 'Answer: D \nExplanation: No contrast material is used in MRCP. It is performed with the use of heavily T2-weighted MR pulse sequences.\xa0On heavily weighted T2 sequences, stationary or slow-flowing fluid within the bile and pancreatic ducts appear very bright relative to the low signal intensity produced by adjacent solid tissues.\nMagnetic resonance cholangiopancreatography (MRCP)\n\nMagnetic resonance cholangiopancreatography (MRCP) is a noninvasive technique for evaluating the intrahepatic and extrahepatic bile ducts and the pancreatic duct.\nUnlike conventional endoscopic retrograde cholangiopancreatography (ERCP), MRCP does not require contrast material to be administered into the ductal system. Thus, the morbidity associated with endoscopic procedures and contrast materials is avoided. However, MRCP does not currently allow any intervention to be performed, such as stone extraction, stent insertion, or biopsy.\nThe technique is performed with the use of heavily T2-weighted MR pulse sequences. These had the effect of making stationary or slow-flowing fluid within the bile and pancreatic ducts to appear very bright relative to the low signal intensity produced by adjacent solid tissues.\nPulse sequences used in MRCP are RARE (rapid acquisition with relaxation enhancement) and HASTE (half-Fourier acquisition single-shot turbo spin-echo)\nMRCP has established a role in the investigation of many biliary disorders, serving as a non-invasive alternative to endoscopic retrograde cholangiopancreatography (ERCP).', 'role': 'assistant'}]