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.
While 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 polycystic ovary syndrome (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, a mean body mass index of 31.5 kg/m
They underwent TAUS that was 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 (body mass index greater than 30), 12 overweight (BMI of 25–29.9), and 9 lean (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, vs. 66 nmol/L in the lean group). They also had greater insulin resistance, as measured by the homeostasis assessment model (5.1 and 3.3, vs. 2.0 in the lean group).
Total testosterone levels were not statistically different between the three BMI groups. Everyone in the lean group had at least one enlarged ovary, as did slightly over half of the overweight and obese groups. Bilateral ovarian enlargement was present in 33%–44% of the girls in each group.
In an interview, Dr. Flannery said that most of the adolescent girls referred to their specialty clinic are obese with symptoms that may be consistent with signs of puberty. It is a challenge to differentiate between girls with early or established PCOS versus girls with just obesity and insulin resistance. Examination of ovarian morphology provides another tool for diagnosis, she said.
Dr. Flannery stated that neither she nor Dr. Burgert had any financial disclosures.