This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cerebrovascular, Subject name: Medicine
[{'content': 'Extradural hemorrhage is seen as: \nSelect and explain. \nA. Hyperdense biconvex, B. Hypodense biconcave, C. Hyperdense biconcave, D. Hypodense biconvex', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (a) Hyperdense biconvexRef: Harrison's 17th ed. Ch 364* Extradural hemorrhage: Bleeding occurs between skull and duramatter. Bleeding occurs due to the rupture ofMiddle meningeal artery. Lucid Interval (Consciousness between two periods of unconsciousness) exists.* In NCCT it shows hyperdensity bleeding, bi-convex or flame shaped bleed.* Treatment: Burr hole surgery.* Subdural hemorrhage: Occurs due to rupture of Cortical bridging veins. In NCCT it shows concavo- convex or sickle shaped bleed.", 'role': 'assistant'}]