This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal Radiology, Subject name: Radiology
[{'content': 'Accordian sign is seen in \nSelect and explain. \nA. Pseudomembranous colitis, B. Intussusception, C. Ileocecal TB, D. Ischemic colitis', 'role': 'user'}, {'content': "Answer: A \nExplanation: The 'Accordion sign' (also known as 'conceina sign') is seen on CT examinations of the abdomen Refers to the similarity between the thickened oedematous wall of Pseudomembranous colitis and the folds of an accordion. This appearance is the result of hyperaemic enhancing mucosa stretched over markedly thickened submucosal folds. Also seen when contrast is trapped between oedematous haustral folds and pseudomembranes formed on the luminal surface of the colon.", 'role': 'assistant'}]