title: Radiation fibrosis: differentiation from recurrent tumor by MR imaging.
abstract: Magnetic resonance (MR) images of 21 patients who had undergone radiation therapy were analyzed and compared with those of 15 patients who had untreated tumors. T2-weighted images (TR = 1,500 msec, TE = 90 msec) were most helpful in distinguishing recurrent tumor from radiation fibrosis. Radiation fibrosis, like muscle, usually remained low in signal intensity on T2-weighted images, while tumor demonstrated higher signal intensity. In no patient was the signal intensity of tumor the same or less than muscle on the T2-weighted images. However, relatively high signal intensity on T2-weighted images is not specific for tumor recurrence and may be seen in acute radiation pneumonitis, infection, hemorrhage, and even pulmonary radiation fibrosis.
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000532:radiotherapy; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy; D008223:Lymphoma / Q000532:radiotherapy; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D011832:Radiation Injuries / Q000175:diagnosis*; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy