Polycystic ovary syndrome: Pelvic MRI as alternative to pelvic ultrasound for the diagnosis in overweight and obese adolescent girls.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common reproductive endocrinopathy in women of childbearing age, affecting 5-15% women in this age group. Suggestive cardinal features comprise hyperandrogenism, ovulatory dysfunction and/or polycystic ovary appearance. The gold standard radiological tool is the pelvic ultrasound (PUS) whose yield may be limited in overweight and obese adolescent girls.

OBJECTIVE AND HYPOTHESES: To evaluate the contribution of pelvic MRI to the diagnosis of PCOS in a specific group of virginal overweight and obese adolescent girls.

METHOD: Eight adolescent girls seen for menstrual irregularities or amenorrhea, with features of hyperandrogenism were biochemically screened (LH, FSH, testosterone, S-DHEA, delta-4 androstenedione, 17 (OH) P, SHBG, TSH, free T4, prolactin and lipid profile, fasting blood sugar and HOMA-IR and HOMA-B). Each had PUS and/or pelvic MRI (PMRI) performed. Other causes of hyperandrogenism were excluded.

IMAGING: PUS with the trans-abdominal transducer was attempted in only one patient Acuson© scanner, using 3.5-7.5 MHz transducer; PMRI was performed in all patients with phased array coil of 1.5 T Siemens MRI scanner, with T1 and T2-weighted axial and coronal images. PCOS was defined according to the Rotterdam PCOS consensus Workshop.

RESULTS: Eight girls (mean age 14,6 ± 1.47 years) are reported, one was overweight (BMI Z-score > 1 SDS), seven others were obese (BMI Z-score > 2 SDS). Mean age at menarche was 11.58 ± 1.11 years, except for one who had not yet entered menarche. All had menstrual irregularities, acanthosis nigricans, acne, hirsutism, and biochemical characteristics of PCOS (high plasma androgens, insulin resistance, glucose/insulin ratio <4.5, decreased SHBG).PUS was not contributive to the diagnosis of PCOS, whereas PMRI showed typical aspect (well delineated peripheral ovarian cysts), with increased ovarian volume and stroma.

CONCLUSION: Although PUS remains the gold standard for the diagnosis of PCOS in most cases, its limitations in overweight and obese girls are real and must be considered.If utilization of endovaginal transducer not being feasible in young virginal girls, PMRI could be a useful alternative, allowing greater delineation of structural components of the ovary and better appreciation of both its volume and structural alterations.