Value of dynamic enhanced magnetic resonance imaging for distinguishing between ovarian fibroma and subserous uterine leiomyoma

Purpose: The purpose of this study was to assess the accuracy of magnetic resonance imaging (MRI), particularly, dynamic MRI, in distinguishing ovarian fibromas from subserous uterine leiomyomas. Material and Methods: Fifteen ovarian fibromas and 15 subserous uterine leiomyomas were retrospectively reviewed. All MR examinations included dynamic contrast-enhanced (DCE) sequences. Morphological criteria (size, T1 and T2 signals, ovarian tissue, associated uterine leiomyoma, and pelvic fluid), arterial vessels, time-intensity curves (maximal enhancement and signal intensity at 30, 60, and 90 seconds), and signal intensity on delayed T1-weighted images were compared between the 2 groups. Results: No significant difference in morphological criteria was noted between the 2 types of masses. Visualization of arterial vessels was more frequent in uterine leiomyomas than in ovarian fibromas (P = 0.002). The DCE MR enhancement rate was higher for uterine leiomyomas than for ovarian fibromas in terms of both maximal enhancement (P < 0.001) and enhancement rate at 30 (P = 0.009), 60 (P= 0.007), and 90 seconds (P= 0.0009). On delayed T1 postcontrast sequence, no statistical difference exists between signal intensity of ovarian fibromas and uterine leiomyomas. Conclusion: Our findings suggest that DCE MRI can distinguish ovarian fibromas from uterine leiomyomas and should be used if sonography fails to show the origin of a pelvic mass.