<prompt> Ectopic pregnancy, characteristic finding in USG is -Absence of gestational sac in uterusComplex adnexal massResistance in colored DopplerFree fluid in peritoneal cavity  <response>: The Presence of a non - ovarian complex adnexal mass is the most sensitive and specific USG finding for ectopic pregnancy.USG in radiologyThe presence of a fetal heart beat outside the uterine cavity is pathognomonic for an ectopic pregnancy.USG in radiology 