<prompt> Central dot sign on CT scan is seen inCarolis diseasePrimary sclerosing cholangitisPolycystic liver diseaseLiver hamaoma  <response>: Caroli disease is a congenital disorder comprising of multifocal cystic dilatation of segmental intrahepatic bile ductsalso classified as a type V choledochal cyst, according to the Todani classificationPathologically, belongs to the spectrum of fibropolycystic liver disease which results from in utero malformation of the ductal plateTwo types - simple and peripoal fibrosisImaging features:CTUS MR:central dot sign poal vein radicles completely surrounded by dilated bile ductsCholangiography diagnostic:segmental saccularfusiformbeaded dilatation of intrahepatic bile ducts extending to the periphery of liver up to 5 cm in diameterbridge formation across dilated luminaintraluminal bulbar protrusionsfrequent ectasia of extrahepatic ducts CBDComplications:Intraductal stonesCholangitis and AbscessLiver cirrhosisCholangiocarcinomaTodani classification:Ref: Grainger and Allison;s diagnostic radiology 6th edition, page 797 