The Diagnostic Role of Ultrasound in Polycystic Ovarian Syndrome: A Clinical Perspective

Abstract

Polycystic ovarian syndrome (PCOS) is one of the most widespread endocrine disorders that is said to affect 5-10% of women of reproductive age globally; it is also known as polycystic ovarian disease. Because of an interplay of hormonal dysfunction, ovulatory disturbances, and classic ovarian morphology, the disease may present in varied forms, bringing long-term health consequences such as infertility, metabolic syndrome, type 2 diabetes, cardiovascular disease, and endometrial cancer. Its multifactorial pathophysiology comprises genetic predisposition, insulin resistance and hyperinsulinemia, obesity (particularly central adiposity), and chronic low-grade inflammation along with altered ovarian stromal architecture resulting in follicular arrest and the characteristic "polycystic" appearance. Accurate diagnosis is often hindered because multiple overlapping clinical symptoms are present in thyroid disorders, Cushing's disease, hyperprolactinemia, and congenital adrenal hyperplasia. The Rotterdam Criteria (2003) constitute a widely accepted set of parameters. On these, two of three major features must be present: 1) Oligo-/anovulation, 2) Clinical and/or biochemical evidence of hyperandrogenism, and 3) Polycystic ovaries on ultrasound. The most important diagnostic tool used is an ultrasound (USG), most frequently a transvaginal ultrasound (TVUS), that provides real-time, cost-effective, and non-invasive imaging of ovarian morphology. Diagnostic features in ultrasound defined for polycystic ovaries are: 1) Presence of ≥12 follicles measuring 2-9 mm in diameter in one or both ovaries, 2) Increase in ovarian volume >10 mL in at least one ovary, and 3) Peripheral arrangement of follicles as "string of pearls". Thickened, hyperechoic ovarian stroma is also commonly suggested. Ultrasound has many advantages in the diagnosis of PCOD, such as low cost, accessibility, and the preservation of excellent soft tissue contrast, while avoiding ionizing radiation. In other words, an ultrasound is inexpensive compared to MRI and laparoscopic procedures and does provide a pretty decent image of ovarian structure. On the other hand, TVUS gives great resolution on the structural anatomy compared to the transabdominal approaches. On top of that, ultrasound plays a bigger role than the initial diagnosis; it is also important in monitoring the ovarian response to treatment (e.g., ovulation induction with clomiphene or gonadotropins), observing ovarian volume, and follicular count dynamic changes through time, estimating ovarian reserve, guiding fertility treatment plans (i.e., timing ovulation, assessing risk of overstimulation), checking the endometrium for hyperplasia risk, and differentiating PCOD from other pelvic pathologies (e.g., endometriomas, functional cysts, tumors). Polycystic morphology may get confounded with normal variation in patients presenting in the clinician setting and also might masquerade as other conditions. That being said, ultrasound is an anatomical imaging, providing very limited functional information, and those findings should always be correlated with the clinical presentation and biochemical evaluation (hormonal profile such as testosterone, LH/FSH ratio, DHEAS) to arrive at a Rotterdam Criteria-based diagnosis and exclude other endocrine disorders.