EVALUATION OF OVARIAN MORPHOLOGY IN NORMAL WOMEN IN REPRODUCTIVE AGE: COMPARISON BETWEEN MRI AND USG.

Abstract

BACKGROUND: Measurements of ovarian volume and antral follicle count (AFC) are a part of diagnostic criteria of polycystic ovarian syndrome (PCOS), and used as a marker in the estimation of ovarian follicular reserve for prognostic purposes in infertility care. There is a growing need to assess the performance of modern techniques in ovarian imaging for clinical, as well as, scientific purposes.
OBJECTIVES: To access ovarian morphology and volume using MRI in young eumenorrheic females in reproductive age group (15-40 years) and to compare MRI obtained measurements and morphologic parameters with USG derived measurements.
STUDY METHOD: Prospective cross-sectional study
PARTICIPANTS: A total of 50 females ranging in age from 15 to 40 years (mean 27 years) were enrolled in our study. Out of these 25 patients had been referred for MRI for other unrelated conditions and 25 healthy volunteers who had no relevant complaints were taken as controls.AU
MATERIALS AND METHODS: Ovarian volume and area was calculated using semi-automated software by marking the boundaries manually in all the sections by the caliper on MRI. On USG (transabdominal) the ovarian and follicular volume was calculated using the formula for prolate ellipsoid (length x width x height x 0.523) and the stromal and ovarian area was calculated using semi-automated software by manually outlining the boundaries using the trackball.
RESULTS: Mean ovarian volume as determined by MRI (6.8 ±2.47 ml) was found to be significantly lesser (p-value=.004) than that found on USG (7.38±2.69 ml). The AFC as seen on MRI (8.85±3.35) was found to be significantly higher (p-value=0.006) than as seen on USG (6.55±3.5).
CONCLUSION AND IMPLICATIONS: MRI was found to be a superior modality for the assessment of the total follicular count which was found to be underestimated on USG. There was a significant difference in the estimation of ovarian volume between the two modalities. With the more accurate measurement technique on MRI it was concluded that USG overestimates the volume of ovaries. With these parameters being the diagnostic criteria of PCOS, MRI could be used as a preferred modality for diagnosis over USG, save for its high cost and lack of availability.