NEW YORK — Ovarian volume assessed by transabdominal ultrasound correlated strongly with serum testosterone levels in a study of 39 adolescent girls undergoing evaluation for polycystic ovary syndrome.
Although magnetic resonance imaging and transrectal or transvaginal ultrasound (TVUS) may better visualize ovarian follicles, transabdominal ultrasound (TAUS) is a less invasive, cheaper, and more readily available imaging modality to diagnose PCOS, Dr. Clare A. Flannery said in a poster presented at a joint meeting of the Lawson Wilkins Pediatric Endocrine Society and the European Society for Pediatric Endocrinology.
With TAUS, the ovarian volume—the sum of the stromal volume and multiple follicles—can be easily calculated from the three dimensions of the ovary. Elevation of serum testosterone, a well-validated diagnostic criterion for PCOS, has been shown to correlate with typical PCOS using TVUS, but little is known about how accurately it relates to increased ovarian volume in TAUS, said Dr. Flannery of the department of endocrinology–internal medicine at Yale University, New Haven, Conn.
The 39 adolescents had a mean age of 15.3 years and a mean body mass index of 31.5 kg/m
They underwent TAUS scans that were read by a radiologist blinded to all clinical information. Ovarian volume was calculated with three diameter measurements, and total ovarian volume was obtained by adding the volume of both ovaries. They had a mean total ovarian volume of 23.2 cm
Total testosterone levels correlated with both single largest ovary volume and total ovarian volume, as did free testosterone. When ovarian volume was analyzed on a continuum, adolescents whose ovaries were less than 10 cm
Differences were seen between the 18 obese (BMI greater than 30), 12 overweight (BMI of 25–29.9), and 9 lean (BMI less than 25) patients. The overweight and obese groups had lower sex hormone–binding globulin than did the lean group (37 nmol/L and 27 nmol/L, respectively, compared with 66 nmol/L in the lean group). They also had greater insulin resistance.
Total testosterone levels were not statistically different among the three BMI groups, although they trended higher in the obese group (mean total testosterone 56 mg/dL).
In an interview, Dr. Flannery said that the majority of the adolescent girls referred to their specialty clinic are obese with symptoms that may be consistent with signs of puberty, namely irregular periods and acne. It is a challenge to differentiate between girls with early or established PCOS versus girls with just obesity and insulin resistance, she said.
Dr. Flannery said neither she nor Dr. Burgert had any financial disclosures.