Ovarian imaging by magnetic resonance in adolescent girls with polycystic ovary syndrome and age-matched controls

Abstract

Purpose: To compare ovarian morphology in adolescent girls with and without polycystic ovary syndrome (PCOS) using magnetic resonance imaging (MRI).

Materials and methods: In 21 adolescent girls (age 12-18 years) without and 19 adolescents with PCOS (diagnosis based on excessive hair growth and irregular menstrual cycles) ovarian volume, antral follicle count (AFC) per ovary, and follicle size were evaluated. MRI was performed at 1.5 T or 3 T and axial or angled-axial single-shot echo-train spin echo images of 6 mm slice thickness were acquired. In a subset of subjects, 2-mm images were also obtained. PCOS and non-PCOS groups were compared using mixed affects regression.

Results: Mean AFC per ovary and ovarian volume were substantially greater in PCOS subjects compared to non-PCOS subjects. Mean follicle size was similar between groups. Follicles exceeding 10 mm were seen in 2/19 PCOS subjects versus 9/21 non-PCOS subjects. Consistently higher follicle counts were detected in images obtained at 2 mm compared to 6-mm slice thickness.

Conclusion: In adolescence, MRI of the ovary reveals distinct differences between girls with and without PCOS. MRI may help evaluate young patients in whom transvaginal ultrasound is contraindicated.

Keywords: magnetic resonance; ovarian follicles; polycystic ovary syndrome.

Figure 1

Axial T2-weighted single-shot echo-train spin-echo image in an adolescent girl with polycystic ovary syndrome.

Figure 2

Axial T2-weighted single-shot echo-train spin-echo image in an adolescent girl with normal ovaries.

Figure 3

Box-and-whisker plot showing follicle number per ovary (FNPO) in normal adolescent girls and adolescent girls with polycystic ovary syndrome (PCOS). Horizontal small bars represent the 5–95^th percentile range and the boxes indicate the 25–75^th percentile range. The horizontal line within each box corresponds to the median. O, values beyond the 95^th percentile.

Figure 4

Box-and-whisker plot showing ovarian volume in normal adolescent girls and adolescent girls with polycystic ovary syndrome (PCOS). Horizontal small bars represent the 5–95^th percentile range and the boxes indicate the 25–75^th percentile range. The horizontal line within each box corresponds to the median. O, values beyond the 95^th percentile.

Figure 5

Correlation between total ovarian follicle counts using 2 mm sections and 6 mm sections in normal adolescents (n = 15) and adolescent girls with PCOS (n =7). (r value = 0.73, p <0.001)