Three-dimensional power Doppler ultrasound measurement of ovarian blood flow after pituitary suppression in the prediction of ovarian responsiveness during in vitro fertilization treatment.

Abstract

Objective: To evaluate whether three-dimensional (3D) power Doppler ultrasound measurement of ovarian blood flow after pituitary suppression is predictive of ovarian responsiveness during IVF and to compare the predictive value of this test with 3D ultrasound measurement of the antral follicle count and ovarian volume, age, and early follicular phase serum FSH level. Design: Prospective observational study of 53 women undergoing long protocol IVF treatment in a University fertility clinic. Materials/Methods: On the day of pituitary suppression the ovarian volumes were measured and averaged and the antral follicles counted using a 3D ultrasound system with a 5–7.5 MHz transvaginal probe (Medison 530D). The power Doppler and 3D-volume mode were then simultaneously activated in order to capture Doppler signals from each ovary in turn. The same power Doppler settings were used for each patient and were selected after a trial period. The settings maximized signals from the ovary whilst minimizing movement artifact from the neighboring iliac vessels and bowel. The volume data sets were then downloaded onto a PC where a software package (3D View, Kretztechnik) was used to delineate the contours of the ovary. Quantitative analysis of the blood flow within the outlined volume (the ovary) was then achieved by implementing the histogram function. The computer calculated the following indexes: Vascularization Index (VI) characterizing vessel density, Flow Index (FI)—intensity of blood flow, and Vascular Flow Index (VFI) specifying both vascularization and perfusion. The main outcome measure was the number of follicles on the day of hCG administration. We attempted to predict the numbers of follicles produced based on the antral follicle count (AFC), average ovarian volume, age, early follicular phase serum FSH level, and the 3D-Doppler indices described, with the use of multiple linear regression analysis. Results: With the use of univariate analysis only the AFC (P < 0.001) and the average ovarian volume (P = 0.019) significantly predicted the number of follicles. When the analysis was adjusted for all other variables in the model, the AFC was the only factor still highly associated with the number of follicles produced. Conclusions: Three-dimensional power Doppler measurement of the ‘total’ blood flow within an ovary is a novel technique with theoretical advantages over the selection of individual vessels as is necessary with two-dimensional (2D) pulsed and color Doppler ultrasound. The lack of prediction of 3D power Doppler was disappointing and at variance with the results of 2D studies that show that ovarian response is correlated with the maximum velocity of stromal blood flow. However, the power Doppler indices studied do not measure flow velocity but rather the total movement of blood within a volume. Additionally, artifact from iliac vessels and bowel which are included in the transducer sweep and encroach into the ovarian volume is a problem. Continued improvements in technology and experience with 3D power Doppler mean that further, larger studies are required to assess the role of this technique in prediction of ovarian responsiveness.