This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Radiology
Central dot sign is seen in- 
Select and explain. 
A. Caroli's disease, B. Primary sclerosing cholangitis, C. Polycystic liver disease, D. Liver hamartoma
A: Caroli's disease
Answer: A: Caroli's disease 
Explanation: Ans. is 'a' i.e., Caroli's diseaseCentral Dot sign* Central dot sign refers to tiny dots with strong contrast enhancement of portal vein within dilated hepatic bile ducts on CT.* Central dot sign is seen in: -i) Caroli's disease (me. cause)ii) Obstructive jaundiceiii) Prebiliary cystiv) Periportal lymphedema