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

PURPOSE: 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). MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: The soft tissues of the female pelvis showed a characteristic pattern of varying edema after irradiation.