ESPE Abstracts

Background: Polycystic ovarian syndrome (PCOS) diagnosis includes ovarian morphology using transvaginal ultrasound (US). However transvaginal US cannot be used in virginal girls and transabdominal US is not optimal particularly in obese patients.

Objective and hypotheses: To evaluate the validity and reproducibility of ovarian morphology measures using MRI for the diagnosis of PCOS in adolescents.

Method: This case-control study (2006–2015) included 128 pubescent girls aged 11–18 who underwent pelvic MRI. Cases had a high suspicion of PCOS (n=45, hyperandrogenism, oligo-amenorrhea), intermediate (n=8, hyperandrogenism) or low (n=7, oligo-amenorrhea). Controls (n=68, no clinical hyperandrogenism nor oligo-amenorrhea). Using the high suspicion of PCOS vs controls as the reference, we assessed the validity (sensitivity, specificity, area under the ROC curve (AUC)) of follicle number per ovary (FNPO) ≤9 and ≤5 mm, ovarian volume (OV), sphericity index, peripheral distribution of follicles and absence of dominant follicle. Two radiologists independently measured these criteria in 50 girls with a suspicion of PCOS selected at random, to assess reproducibility (kappa, intraclass correlation coefficient (ICC)).

Results: All criteria but sphericity index were significantly associated with the level of suspicion of PCOS (P for trend <0.05). AUC of FNPO ≤9 mm (0.81; 95% CI: 0.73–0.89), FNPO ≤5 mm (0.76; 0.67–0.85) and OV (0.78; 0.70–0.87) were significantly higher than 0.5, contrary to sphericity index (AUC=0.58; 0.47–0.68). The sensitivity and specificity of peripheral distribution of follicles were 37.8% (23.8–53.5) and 95.6% (87.6–99.1). For absence of dominant follicle, they were 93.3% (81.7–98.6) and 23.5% (14.1–35.4), respectively. The reproducibility was almost perfect for OV (ICC=0.88), substantial for absence of dominant follicle (kappa=0.73), moderate for FNPO ≤9 mm (ICC=0.54) and FNPO ≤5 mm (ICC=0.60), fair for peripheral distribution of follicles (kappa=0.39) and slight for sphericity index (ICC=0.14).

Conclusion: The most accurate diagnostic criteria by MRI were FNPO ≤9 mm, OV and peripheral distribution of follicles; the most reliable criterion was OV. MRI is a valuable tool to confirm PCOS in adolescent girls based on clinical and hormonal characteristics when transvaginal US cannot be performed.