This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Trauma, Subject name: Surgery
[{'content': 'What is the investigation of choice in a patient with blunt abdominal trauma with hematuria \nSelect and explain. \nA. Ultrasonography of abdomen, B. Contrast enhanced tomography, C. Intravenous urogram, D. Retrograde urogram', 'role': 'user'}, {'content': "Answer: B \nExplanation: CT Scan of Abdomen: It is most commonly used and better investigation for abdominal trauma. It is useful in blunt/penetrating trauma, suspected pancreas, spleen, liver, duodenal, retroperitoneal injuries. Smaller injuries, early haemoperitoneum are better detected. It is noninvasive, highly specific, highly accurate (96%), with low false-positive/low false-negative, noninvasive. Ultrasound Abdomen -Disadvantages: It is less useful in obesity, with interposition of gas, when fluid is less than 500 ml; retroperitoneal injuries and bowel injuries. SRB's Manual of Surgery, 4th Edition, pg. no. 151", 'role': 'assistant'}]