The endometrial stripe, also called the endometrial echo, is the ultrasound appearance of the endometrium, the lining of the uterine cavity. On transvaginal ultrasound, it appears as a bright, echogenic line running through the center of the uterus, and its thickness is measured from one outer edge of the endometrium to the other in the sagittal plane. In premenopausal women, the endometrial stripe normally varies in thickness from about 1 to 4 millimeters during menstruation to as much as 14 millimeters in the secretory phase. In postmenopausal women not on hormone therapy, a thickness of 4 to 5 millimeters or less is considered normal, and measurements above this threshold in a woman with vaginal bleeding warrant further evaluation.
Sonography Term