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: Radiology
[{'content': 'Which of the following is not a CT feature ofAdrenal adenoma – \nSelect and explain. \nA. Low attenuation, B. Homogenous density and well defined borders, C. Enhances rapidly, contrast stays in it for a relatively longer time and washes out late, D. Calcification is rare', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Adrenal adenoma on contrast-enhanced CT/MRI shows rapid uptake and relatively rapid washout of contrast\xa0material than do non\xa0adenomasQ.\nAdenoma: CT features\n\nWell defined/sharply defined\xa0\n<5 cm in size\nLow attenuation (<10 HU) due to lipid content\nMild homogenous enhancement\nRelatively rapid washout of contrast material (due to lack of large interstitial spaces\nRelatively rapid washout\xa0is characteristic of adenoma', 'role': 'assistant'}]