Figure 4b. Hyperechoic line related to an underlying endometrial polyp. (a) Transverse endovaginal US scan shows a hyperechoic line surrounding the central endometrial complex (arrowheads). There are also cystic spaces within the central endometrial complex (arrows). (b) Subsequently obtained longitudinal hysterosonogram shows an endometrial polyp (arrow) with a narrow attachment to the endometrium (arrowheads).