This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': 'Shape of post traumatic Epidural hematoma is \nSelect and explain. \nA. Biconvex hyperdense, B. Biconvex hypodense, C. Biconcave hyperdense, D. Biconcave hypodense', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Biconvex hyperdense > Epidural hematoma. Head CT after traumatic brain injury reveales a classic biconvex hyperdensity diagnostic of an epidural hematoma (arrow). There is mass effect and midline shift to the left.> Epidural Hematoma: The CT classically will show a hyperdense lesion (hematoma) that is biconvex or lens-shaped secondary to its position between the dura and the skull.', 'role': 'assistant'}]