Magnetic Resonance Imaging of the Ovaries of Healthy Women: Determination of Normal Values

Purpose: To establish normal values for the volume and maximal diameter of ovaries and ovarian follicles and for the number of ovarian follicles in magnetic resonance imaging (MRI) based on menstrual cycle phase and age. Material and Methods: We performed MRI of the pelvis on 100 healthy women. Volume of the ovaries and largest ovarian follicles and the number of ovarian follicles were determined by menstrual cycle phase and age. Results: The mean volume of the ovaries significantly increased with age and reached its peak between 31 and 40 years, and subsequently decreased. The mean volume of the largest ovarian follicles also significantly increased with age to reach its peak at 41-50 years. The highest mean numbers of ovarian follicles were found at 20-40 years. When the volumes of ovaries and of the largest ovarian follicles, and the number of ovarian follicles were compared between the first and second phase of the menstrual cycle, no significant differences were found. Conclusion: The volume and maximal diameter of ovaries and ovarian follicles and the number of ovarian follicles differ significantly with age, but not between the two phases of the menstrual cycle. Knowledge of MRI-related normal values can be expected to aid the early identification of ovarian pathologies.