Cycle-related changes in the appearance of the endometrial stripe (EMS) on transvaginal ultrasound. A, Early proliferative endometrium. B, Late proliferative endometrium. C, Early secretory endometrium. D, Late secretory endometrium. Opposing arrows on each image demonstrate correct cursor placement to measure thickness of the EMS. Ultrasound School, Medical Ultrasound, Vascular Ultrasound, Ultrasound Sonography, Sonography Student, Diagnostic Medical Sonography, Radiology Imaging, Medical Imaging, Obstetric Ultrasound