Bridging vessel sign refers to an appearance of multiple vessels crossing from uterus to a juxta-uterine pelvic mass and it helps to differentiate a subserosal leiomyoma from other pelvic masses. 

This case clearly demonstrates multiple curvilinear flow voids extending from the anterior myometrium of uterus through the broad stalk into the subserosal leiomyoma.

The diagnosis was achieved based on the typical imaging features.