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
Ring of fire on USG signifies? 
Select and explain. 
A. H. mole, B. Ectopic pregnancy, C. PCOD, D. Aneuploidy
B: Ectopic pregnancy
Answer: B: Ectopic pregnancy 
Explanation: Ans. is'b'i.e., Ectopic pregnancyThe ring of fire sign also known as ring of vascularity signifies a hypervascular lesion with peripheral vascularity on colour or pulsed doppler examination of the adnexa due to low impedance high diastolic flow.This sign can be seen inCorpusluteum cyst (more commonly)Ectopic pregnancy