Dating sonographic endometrial images in the normal ovulatory cycle.

Pelvic sonograms were obtained from 5 fertile volunteers and 150 infertile patients with normal ovulatory cycles, using real-time ultrasound. The existence of a linear cavity echo (C), thick hypoechoic layer (H) and increased echogenicity (E) were chosen as the parameters of sonographic endometrial images to be studied for dating the ovulatory cycle. In 109 serial sonograms from the fertile volunteers, H was observed from 3 days before ovulation (day -3) to ovulation day (day 0). E was observed from day +1 to day +8, and C, from day -10 to day +3. Studies on 189 sonograms from the infertile patients revealed a similar pattern for these parameters. We tested the accuracy of sonographic images of the endometrium, using sonograms from five patients who underwent hysterectomy. The measurements of endometrial thickness, in vivo, and in vitro, showed little difference. Sonographic endometrial images are considered indicative of histological changes, under the influence of estradiol and progesterone. Therefore, observation of the combined quantitative changes in C, H and E facilitates dating of the sonographic endometrial images in a normal ovulatory cycle.