Noncritical soft tissues of the female pelvis: Serial MR imaging before, during and after radiation therapy

The purpose of this study was to present the findings of the irradiated noncritical soft tissues of the female pelvis at magnetic resonance (MR) imaging within 18 months after radiation therapy (RT). The soft tissues of the pelvis of 24 women with advanced cervical carcinoma were studied in 240 MR examinations scheduled before, three times during, and 7 weeks and 3, 6, 9, 12, and 18 months after RT. Two radiologists visually evaluated the signal intensity (SI) of the subcutaneous fat, muscles, and presacral space (PS) on T1- and T2-weighted and short inversion time inversion-recovery images. SI compatible with edema appeared in the PS, pelvic muscles, and subcutaneous fat within 3 months after the end of RT and was observed in 23 (96%) of the 24 patients. During the observation period, the edema subsided. Eighteen months after treatment, edema in the PS was seen in 12 (50%) of the 24 patients. The soft tissues of the female pelvis showed a characteristic pattern of varying edema after irradiation. 27 refs., 12 figs