Diagnostic Ultrasound - Abdomen and Pelvis

Polycystic Ovarian Syndrome
TERMINOLOGY
Abbreviations
• Polycystic ovarian syndrome (PCOS)
Synonyms
• Stein-Leventhal syndrome: Hyperandrogenemia
→polycystic ovaries, hirsutism, menstrual abnormalities,
obesity
Definitions
• Complex heterogenous syndrome of ovulatory
dysfunction, menstrual irregularity, and androgen excess
• Rotterdam criteria for PCOS developed in 2003: 2 of 3
criteria must be present
○ Oligo- or anovulation
○ Hyperandrogenism (clinical or biochemical)
○ Polycystic ovaries (by ultrasound)
• Polycystic ovarian morphology (PCOM) is better term for
ovaries meeting criteria on ultrasound because many
women do not have PCOS
IMAGING
General Features
• Best diagnostic clue
○ Enlarged ovaries with volume > 10 mL or
○ ≥ 12 follicles per ovary measuring 2-9 mm in diameter
Ultrasonographic Findings
• Grayscale ultrasound
○ Uterus often enlarged due to estrogenization
○ Ovarian stromal ↑ echogenicity
○ ↑ ovarian stromal volume
– ↑ stromal volume is main cause of ↑ ovarian volume
(follicles do not contribute significantly)
Imaging Recommendations
• Best imaging tool
○ Transvaginal ultrasound because of↑ resolution
• Protocol advice
○ Measure ovarian diameters in 3 planes
○ Calculate volume using formula for prolate ellipsoid
(longitudinal x transverse x AP diameter x 0.5233)
– Normal women 7.94 ± 2.34 cc
– PCOS patients 10.04 ± 7.36 cc
○ Follicle numbers should be assessed in at least 2 planes
to confirm size and position
○ Follicle diameter should be measured as mean of 3
planes
○ If dominant follicle (> 10 mm diameter) or corpus luteum
seen, repeat scan during next cycle to avoid false
elevation of volume
○ Regularly menstruating women should be scanned day
3-5, oligo/amenorrheic women can be scanned at
random or 3-5 days after progestogen-induced bleed
DIFFERENTIAL DIAGNOSIS
Normal
• Ovarian morphology alone is insufficient for diagnosis of
PCOS
○ Polycystic ovarian morphology (PCOM) seen in ~ 22% of
women, PCOS prevalence is only 5-10%
Suppressed Ovary
• Oral contraceptive pills suppress ovulation → multiple small
follicles
Other Causes of Hyperandrogenism
• Hyperthecosis, congenital adrenal hyperplasia, 21-
hydroxylase deficiency, Cushing syndrome, androgen
producing neoplasm
PATHOLOGY
General Features
• Etiology
○ No single etiologic factor identified, no responsible gene
as yet isolated
○ Likely complex interaction between genetics and
environmental/metabolic factors
• Associated abnormalities
○ Obesity, hirsutism
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ PCOS phenotype has 3 components
– Anovulation → oligo/amenorrhea
– Hyperandrogenism → hirsutism
– Obesity with associated hyperinsulinemia/insulin
resistance
Demographics
• Epidemiology
○ Most common cause of anovulatory infertility in USA
○ Affects 6-10% of females in reproductive age group
Natural History & Prognosis
• Associated with dysmetabolic syndrome
○ 3-7x ↑ risk maturity onset diabetes, some studies
suggest ↑ cardio/cerebrovascular events
Treatment
• Traditional treatment centers on ovulation induction,
treatment of acne/hirsutism, prevention of endometrial
cancer, diabetes, and heart disease risk
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Features seen in 1 ovary are sufficient to diagnose PCOS
• Ovarian volume is suppressed in women taking oral
contraceptives but appearance may still be polycystic
SELECTED REFERENCES
1. Dewailly D et al: Definition and significance of polycystic ovarian
morphology: a task force report from the Androgen Excess and Polycystic
Ovary Syndrome Society. Hum Reprod Update. 20(3):334-52, 2014
2. Lujan ME et al: Updated ultrasound criteria for polycystic ovary syndrome:
reliable thresholds for elevated follicle population and ovarian volume. Hum
Reprod. 28(5):1361-8, 2013
Diagnoses: Female Pelvis
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