Uterine MR imaging: effects of hormonal stimulation.

Magnetic resonance (MR) imaging characteristics of the uterine corpus were evaluated in 40 women divided into five physiologic categories (nine premenarchal, 13 reproductive age not taking hormones, seven reproductive age taking oral contraceptives, six reproductive age taking gonadotropin releasing hormone analog, and five postmenopausal). Images were generated using a 0.35-T magnet and a double spin-echo technique. On both T1-weighted and T2-weighted images, premenarchal and postmenopausal uteri were small and relatively featureless. Uteri on T2-weighted images in reproductive age women not taking exogenous hormones showed variations in endometrial and myometrial width, signal intensity, and T1 and T2 values during the menstrual cycle. Oral contraceptives and gonadotropin releasing hormone analogs caused endometrial atrophy and alterations in myometrial signal intensity and T1 and T2 values. A detailed gynecologic history is therefore essential in the evaluation of uterine anatomy in patients undergoing pelvic MR imaging.