RESEARCH QUESTION: Does formation of the corpus luteum help to identify the day of ovulation on ultrasound when follicular collapse is missed, and how reliable are sonographers versus a review panel in identifying the day of ovulation on ultrasound?
Design
Sonographers in a clinic in Canada performed serial endovaginal ultrasound scans (six to eight per cycle) to identify the day of ovulation in regularly cycling women (n = 40) who were followed for one to five cycles (n = 85). The day of ovulation was identified by: (i) identification of the dominant follicle; (ii) disappearance of the dominant follicle; and (iii) identification and dating of the corpus luteum. The main outcome measures were inter-rater reliability between two sonographers, and Bland-Altman agreement between the supervising sonographer and a panel that reviewed each scan to identify the day of ovulation.
Results
Of the 85 menstrual cycles reviewed, two cycles did not have sufficient data to date ovulation, one cycle showed an incidental dermoid cyst, and 11 cycles showed anovulatory patterns. This left a total of 71 cycles (84%) for which intra-rater reliability between two sonographers for identifying the day of ovulation was high (intraclass correlation coefficient = 0.99, P < 0.0001), and Bland-Altman agreement showed no significant difference in the estimated day of ovulation between the supervising sonographer and the panel (t = -0.28, P = 0.78). Corpus luteum criteria were necessary to help identify the day of ovulation in 14 of 71 cycles (20%).
Conclusions
The estimated day of ovulation can be determined reliably on ultrasound by trained sonographers using collapse of the dominant follicle and formation of the corpus luteum based on six to eight scans per cycle.
Ecochard R et al., 2000·European journal of obstetrics, gynecology, and reproductive biology
Evaluation of sensitivity and specificity of 4 ultrasound indices of ovulation. Multicenter collaborative study of 794 abdominal and transvaginal ultrasound scanning of ovaries performed during 271 cycles in 107 normally fertile women. Comparison of sensitivities and specificities of indices using McNemar test. The sensitivity and specificity of the indices were 84 and 89.2, respectively, for disappearance or sudden decrease in follicle size; 38.4 and 79.7 for appearance of ultrasonic echoes in the follicle; 61.6 and 87.1 for irregularity of follicular walls; 71.0 and 88.2 for appearance of free fluid in the cul-de-sac of Douglas. Ultrasonic echoes had a significantly lower sensitivity (P<0.001) and specificity (P<0.01) than other indices.
Sonographic visualization of the cumulus oophorus or of morphologic alterations in the wall of the dominant follicle have been reported to be reliable signs of imminent ovulation when conventional transabdominal sonography is used. To determine if transvaginal sonography could allow a more frequent and confident prediction of imminent ovulation, we prospectively monitored 22 ovulatory menstrual cycles in four women undergoing artificial insemination and in 13 normally menstruating volunteers. Scanning was done on alternate days in the periovulatory period; a 7.5-MHz transvaginal transducer was used. Despite the improved resolution obtained with transvaginal sonography, confident identification of the cumulus oophorus or of mural changes in the follicle was not possible in any of the cycles followed. No other consistent follicular characteristic predicted imminent ovulation. We conclude that confident prediction of imminent ovulation is not possible with sonographic analysis.
Ultrasonographic measurement of follicle growth and estradiol concentrations have been shown to correlate well in spontaneous and Clomid-induced ovulatory cycles. However, little is known about these changes during human menopausal gonadotropin (hMG) therapy. Twenty-five women who did not ovulate when treated with clomiphene were treated with hMG during 70 treatment cycles. Eleven patients had withdrawal bleeding after progesterone administration (group 1) and 14 did not bleed (group 2). Follicle growth was monitored with intermittent serum estrogen determinations and daily ovarian ultrasound with an ADR Model 2140 real-time sector scanner. The mean dominant follicle size at the time of human chorionic gonadotropin (hCG) injection was 21.2 mm +/- 0.6 (SEM) and was not different between the two groups. Mean serum estrogen level at the time of hCG injection was 1,121 pg/ml and correlated with follicle volume. At the time of hCG injection in group 2, one dominant follicle was present in 65% and two were present in 35% of the patients. Among those in group 1, two or more dominant follicles were present during all cycles. Mean serum estrogen levels were significantly higher in group 1 patients than those in group 2. This "chemical hyperstimulation" was induced in order to delay ovulation until adequate follicular size had been achieved. All cycles were ovulatory. Five patients in group 1 and eight in group 2 conceived. The use of ultrasound enables the physician to evaluate follicular growth and development daily and thus to individualize treatment and to reduce the need for estrogen monitoring.
Healthy volunteers with regular ovarian function, women taking oral contraceptives, and infertile patients being treated with clomiphene were studied longitudinally from day 7 of the cycle to menstruation. The main objective was to determine whether ovulation or failure to ovulate could be detected accurately by the use of ultrasound. The ovaries were scanned with a Kretz Combison 100 sector scanner every 1 to 3 days for morphologic changes consistent with follicle development, ovulation, and development of the corpus luteum. The morphologic changes were correlated with daily urinary hormone profiles. The estimated times of ovulation according to ultrasound and luteinizing hormone peak overlapped by 24 hours in 19 of 23 normal cycles and in 5 of 6 cycles of patients treated with clomiphene. Both techniques indicated that three of three women taking oral contraceptives did not ovulate. The ultrasound studies indicated a wide range in the diameter of the preovulatory follicle, which precludes follicular diameter as a single index for prediction of ovulation. However, by measuring the maximal diameter of the follicle and observing the morphologic changes within the ovary from follicle to corpus luteum, it was possible to detect ovulation in more than 80% of cycles studied. This technique was found to be quick, inexpensive, and efficient.