Fig. 2.1
Pathognomonic appearance of the polycystic ovary at laparotomy. Enlarged ovary with multiple small follicles (Image courtesy of Dr. Dorival Gomide Ramos)
The involvement of the hypothalamic-pituitary axis in PCOS has been increasingly reported in other studies, when the biochemical criteria acquired are of paramount importance to its diagnosis [2]. Elevated serum levels of luteinizing hormone, testosterone, and androstenedione, in association with normal or low levels of follicle-stimulating hormone, characterize a profile associated with this pathology [3].
The pathophysiology of PCOS is not completely understood. Between 16% and 25% of healthy women may show morphology of polycystic ovaries on ultrasound without associated hormonal changes [4], and the development of PCOS requires additional factors [5, 6]. At any rate, its early diagnosis is essential for identifying the potential risk of metabolic disorders and cardiovascular diseases. Many of these patients show a resistance to insulin and hyperinsulinemia, abnormal levels of lipoproteins, and lipids and fibrynolisis changes (Scheme 2.1).
Scheme 2.1
Pathophysiology of polycystic ovary syndrome
The clinical presentation is variable, but usually includes trace or anovulation, hyperandrogenism (clinical and/or laboratory,) and the appearance of polycystic ovaries. A combination of these three conditions − or all of them − may be present, so the diagnosis is a complex challenge and a controversial issue.
In 1990 at a conference on PCOS, the U.S. National Institutes of Health (NIH) recommended that the diagnostic criteria include hyperandrogenism with no other apparent causes, such as adrenal hyperplasia and ovulatory dysfunction. The morphology of polycystic ovaries in ultrasound has been considered prevalent, but not essential for diagnosis [7].
The need to redefine PCOS and to include an ultrasound aspect of polycystic ovaries in the diagnosis prompted a consensus meeting of the ASRM/ESHRE that took place in 2003 in Rotterdam. According to this new setting, the diagnosis of PCOS requires the presence of two of the following three criteria: Oligo/anovulation; hyperandrogenism (clinical and/or laboratory); and polycystic ovaries, excluding other etiologies [8]. Thus there are two definitions in the literature for PCOS (Table 2.1); at any rate, PCOS usually manifests in the early years of reproductive life and is considered the most common endocrine disorder in women. A prevalence of 6–10% is estimated, according to criteria of the NIH, and up to 15% when the Rotterdam consensus parameters are used [9].
Table 2.1
Polycystic Ovary Syndrome definitions
Authors | Criteria |
|---|---|
NIH, 1990 | Hyperandrogenism, without other causes; and oligo/anovulation |
ASRM/ESHRE Rotterdam, 2003 | Two of three: Oligo/anovulation Hyperandrogenism Polycystic ovary on ultrasound |
In 2010 there was a new ASRM/ESHRE consensus meeting in Amsterdam, where special attention was paid to the diagnosis of PCOS in adolescent patients. For this group, the diagnosis of PCOS when the following three parameters are present is considered: Oligo/anovulation; hyperandrogenism (clinical and/or laboratory); and polycystic ovaries, excluding other etiologies [9].
Imaging Findings
The findings of ovaries with polycystic morphology can be quite common in the imaging methods of the female pelvis. In a study involving 230 women between the ages of 18 and 25, the morphology of polycystic ovaries was found on ultrasound in 74 (33%) of them [10]. About 80% of these patients had signs and symptoms of PCOS, usually moderate, while 20% did not have any hormonal or ovulatory change [4].
Pelvic ultrasound is the most commonly used method for identifying polycystic ovaries. It is easy to visualize the increased volume of ovaries with more evident stroma and multiple small follicles that make up the appearance of small cysts that are very different from the normal ovary (Figs. 2.2 and 2.3).
Fig. 2.2
Transvaginal sagittal image of normal ovary
Fig. 2.3
Transvaginal image of polycystic ovary. The enlarged ovary with more evident stroma and multiple small follicles that make up the appearance of small cysts
The transvaginal approach is the best one for identifying polycystic ovaries, mainly due to increased spatial resolution that makes a detailed assessment of the internal structures of the ovaries possible. Often an ovary that has a more homogeneous echotexture by the abdominal approach shows polycystic morphology in transvaginal examination, especially in obese patients. The detection of polycystic ovaries is virtually the same (about 78%) on transabdominal and transvaginal ultrasound ovaries [11].
In 1985, Adams et al, still using transabdominal ultrasound, defined a polycystic ovary as one that in a single cutting plane has at least 10 follicles, that is usually between 2 and 8 mm in diameter, and is distributed circumferentially around a central dense stroma [12] (Figs. 2.4, 2.5, 2.6 and 2.7) Many other studies used the Adams criteria for the diagnosis of polycystic ovaries, and one of them concluded that viewing polycystic ovaries in ultrasound could be the key to the diagnosis of PCOS in patients with signs and symptoms [13].
Fig. 2.4
Transabdominal image of a polycystic ovary as described by Adams: at least 10 follicles, usually from 2 to 8 mm in diameter, distributed circumferentially around a central dense stroma
Fig. 2.5
Transvaginal image of a polycystic ovary as described by Adams: at least 10 follicles, usually from 2 to 8 mm in diameter, distributed peripherally around a central dense stroma
Fig. 2.6
Transvaginal image (axial view) of a polycystic ovary as described by Adams: at least 10 follicles, usually from 2 to 8 mm in diameter, distributed peripherally around a central dense stroma
Fig. 2.7
Transvaginal image of a polycystic ovary as described by Adams: at least 10 follicles, usually from 2 to 8 mm in diameter, distributed peripherally around a central dense stroma
Over time, a number of other descriptions have been proposed to set the morphology of polycystic ovaries on ultrasound, all based on the main histologic features: excessive number of follicles, and stroma hypertrophy. The increase in ovarian volume or the stroma area, stromal hyperechogenicity, the relationship between the stromal and ovarian areas, and the relationship between the ovarian and uterine volumes were also described and the parameters were tested.
The denser ovarian stroma is an important parameter for histopathologic diagnosis [14]. In ultrasound, the ovarian stroma should theoretically be less echogenic than the myometrium [8]. The hyperechoic stroma (Fig. 2.8) had a sensitivity of 94% and specificity of 90% for the diagnosis of polycystic ovaries in a study that compared women with PCOS with a control group [15]. In a study in which the echogenicity of the stroma was measured in a formula that took into account the number of pixels per area examined, the values found in PCOS patients were not significantly different [16].
