Ovarian factor infertility.

Abstract

The diseases of the ovary which most frequently cause infertility are: anovulation from follicular atresia, the empty follicle syndrome, the luteinized unruptured follicle syndrome; chronic anovulation syndromes, within which polycystic ovarian syndrome plays a major role; ovarian endometriosis. Sonography and Color Doppler US are the first choice procedures in the monitoring of ovarian cycles, which combined with serum hormone values, are able to identify possible changes in the physiologic sequence of the cycle. In follicular atresia, ovaries with minute follicles (3mm or less) and early disappearance of primary follicle are observed on sonography. The empty follicle syndrome characterized by the lack of oocytes within the primary follicle, is of difficult sonographic diagnosis, a possible sign being the missed visualization of cumulus oophorus. The luteinized unruptured follicle syndrome consists in the absence of oocyte expulsion from primary follicle persisting more than 48 hours after LH blood peak. Doppler spectra of blood flow in perifollicular ovarian arteries maintain the features of the follicular phase, i.e. low diastolic velocities and high resistances. Among chronic anovulation syndromes, hyper-and hypogonadotropism cause ovarian amenorrhea where ovaries are similar to those of women in menopause: small size, very few or absent follicles. The polycystic ovarian syndrome is characterized by an abnormal pulsatile GnRH release which causes LH hypersecretion and FSH hyposecretion. The latter is not able to stimulate the growth and maturation of follicles, while the former causes hyperandrogenism with hirsutism and obesity and is responsible for hypertrophy and stromal hyperechogenicity. The sonographic diagnosis of polycystic ovarian syndrome is based on standardized morphostructural signs as increased volume of the ovaries (> 10 cm3), the presence of numerous (> or = 10) peripheral microfollicles (< or = 5 mm) with hyperechoic stroma. The endometrial cyst, usually present in ovarian endometriosis is visualized with sonography as a round neoformation with ill-defined walls, filled with a uniformly hypoechoic, corpuscular, partly hemorrhagic fluid; less frequently the appearance is that of a more complex structure posing differential diagnostic problems, mainly with the hemorrhagic corpus luteum; both pathological conditions appear poorly vascularized at Color Doppler, with tracings of high resistance arterial flow. Among the procedures of second choice, CT can show the high blood density common to the two conditions while on MRI the signal is mostly hyperintense in T1-weighted sequences with areas of lower signal intensity in T2-weighted sequences.