Follicle number not assessments of the ovarian stroma represents the best ultrasonographic marker of polycystic ovary syndrome

As a single metric, follicle number per ovary best predicts PCOS. Ovarian volume and follicle number per single cross-section, together, provide the closest level of diagnostic potential to follicle number per ovary alone. Stromal measurements have little to no diagnostic potential.


Jacob P. Christ, B.S., Amy D. Willis, B.Act.St., Eric D. Brooks, B.S., Heidi K. Vanden Brink, M.Sc., Brittany Y. Jarret, B.S., Roger A. Pierson, Ph.D., Donna R. Chizen, M.D., Marla E. Lujan, Ph.D.

Volume 101, Issue 1, Pages 280-287.e1, January 2014



To compare the diagnostic potential of ultrasonographic markers of ovarian morphology, used alone or in combination, to predict polycystic ovary syndrome (PCOS).


A diagnostic test study using cross-sectional data collected from 2006–2011.


Academic hospital and clinical research unit.


Eighty-two women with PCOS and 60 healthy female volunteers.



Main Outcome Measure(s):

Follicle number per ovary (FNPO), ovarian volume (OV), follicle number per single cross-section (FNPS), follicle distribution pattern, stromal area, ovarian area, stromal-to-ovarian area ratio (S:A), and stromal index (SI).


Follicle number per ovary best predicted PCOS (R2 = 67%) with 85% sensitivity and 98% specificity, followed by OV (R2 = 44%), and FNPS (R2 = 36%). Neither S:A nor SI had predictive power for PCOS. In combination, FNPO+S:A and FNPO+SI most significantly predicted PCOS (R2 = 74% vs. 73%, respectively). The diagnostic potentials of OV and FNPS were substantially improved when used in combination (OV+FNPO, R2 = 55%).


As a single metric, FNPO best predicted PCOS. Although the addition of S:A or SI improved the predictive power of FNPO, gains were marginal, suggesting limited use in clinical practice. When image quality precludes a reliable estimation of FNPO, measurements of OV+FNPS provide the next closest level of diagnostic potential.

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