Ultrasound diagnosis of polycystic ovary syndrome.

The US diagnostic criteria of the PCO have been refined with each successive advance in US technology. Diagnostic accuracy has evolved from a mere appreciation of overall ovarian size to the recognition of characteristic follicular patterns of distribution and subtle textural changes in the ovarian stroma. The most consistent features are the presence of multiple small follicles arranged around, or scattered through, a dense echogenic ovarian stroma, although recognition of the latter is highly subjective. Sophisticated innovations such as 3D US, together with colour and pulsed Doppler US, should improve the objectivity of observations and allow quantitative analysis of the ovarian stroma, which is known to be the source of the characteristic hyperandrogenaemia in PCOS. Valid comparative studies of women with normal and polycystic ovaries should now be feasible and will hopefully bring us closer to understanding the pathogenesis of this fascinating condition.