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': "Central dot sign is seen in: \nSelect and explain. \nA. Caroli's disease, B. Primary sclerosing cholangitis, C. Polycystic liver disease, D. Liver hamaoma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: A. i.e. Caroli\'s disease Central dot sign is considered pathognomonic of carolis diseaseQ. This sign consists of cystically dilated intra hepatic biliary radicles with a "dot" of increased density represented by poal radicle with the lumen of duct. Caroli\'s disease Communicating cavernous ectasia of the intrahepatic bile ducts. (IHBD). - AR congenital disorder - Segmental, saccular dilatation of the IHBD. - A/W: - Choledochal cyst and - AR polycystic kidney disease (ARPKD) Signs Disease Central dot signQ Caroli\'s disease Pruned- Tree appearance / Beaded appearenceQ / Skip lesions Primary sclerosing cholangitis Light bulb appearance Liver Hemangioma (on T2W MRI) Water lily sign /HoneycombingQ Liver hydatid', 'role': 'assistant'}]