<prompt> True about ectopic pregnancy:Transvaginal USG-first imaging test of choiceNot Associated with decidual reactionDoppler is of no significanceIn ectopic interstitial ring sign is seen  <response>: If TVS reveals an intrauterine gestational sac,the diagnosis of ectopic can usually be ruled out .sometimes a psuedosac may be seen in an ectopic due to bleeding produced by separation of a decidual cast.refer pgno:159 sheila 2 nd edition 