To assess the capability of magnetic resonance (MR) imaging to demonstrate postirradiation changes in the uterus, MR studies of 23 patients who had undergone radiation therapy were retrospectively examined and compared with those of 30 patients who had not undergone radiation therapy. MR findings were correlated with posthysterectomy histologic findings. In premenopausal women, radiation therapy induced (a) a decrease in uterine size demonstrable as early as 3 months after therapy ended; (b) a decrease in signal intensity of the myometrium on T2-predominant MR images, reflecting a significant decrease in T2 relaxation time, demonstrable as early as 1 month after therapy; (c) a decrease in thickness and signal intensity of the endometrium demonstrable on T2-predominant images 6 months after therapy; and (d) loss of uterine zonal anatomy as early as 3 months after therapy. In postmenopausal women, irradiation did not significantly alter the MR imaging appearance of the uterus. These postirradiation MR changes in both the premenopausal and postmenopausal uteri appeared similar to the changes ordinarily seen on MR images of the nonirradiated postmenopausal uterus.
