Background: The introduction of transvaginal approach in ultrasound (US) has enabled the accurate evaluation of the structure of the ovary and stroma. Stroma represents an acknowledged US marker for polycystic ovary syndrome (PCOS). The proportion revealed between the stroma and the ovary surface in the median section (S/A ratio) had been indicated as a reliable marker for hyperandrogenism. In order to verify the feasibility of this determination in routine use and to confirm the efficacy of S/A ratio in predicting hyperandrogenism in PCOS, a multicentric study was performed in association with five Italian research groups.
Methods: A total of 418 subjects of fertile age presenting oligomenorrhoea or secondary amenorrhoea, enlarged ovaries measuring >10 cm(3) and/or >12 follicles measuring 2-9 mm in diameter took part in the study. Clinical, US and hormonal evaluations were performed in the early follicular phase or on random days in amenorrhoeic subjects. US assessment included ovarian volume, follicle number, ovarian and stroma area in median section. The hormonal study included a baseline plasma determination of LH, FSH, estradiol (E(2)), androstenedione (A), testosterone (T), dehydroepiandrosteronesulphate, 17-hydroxy-progesterone, sex hormone-binding globulin and prolactin. Correlations and receiver operator curves were used in statistical analysis of data.
Results: S/A was found to be the best significant predictor of elevated A and T levels. In order to ascertain significant cut-off values in relation to A and T levels Youden indexes were calculated and indicated 0.32 as the best cut-off for the S/A ratio.
Conclusions: This work underlines the importance of stroma measure in improving US diagnosis of PCOS and suggest that this parameter may be used in routine clinical practice. In fact, multicentre study demonstrated the easy feasibility of such procedure without need of sophisticated machines or intensive training for operators.