Using MRI we assessed the changes in signal, size, and contrast enhancement characteristics of the cervical spinal cord in radiation myelopathy developing after radiotherapy for nasopharyngeal carcinoma. We studied two men and five women, aged 40-77 years. The first MRI study was performed 1-4 months after the initial clinical manifestations of myelopathy, and follow-up MRI 2-22 months after the onset of symptoms. On the first study, all patients showed low signal intensity in a long segment of the cervical spinal cord on T1-weighted images, high signal on T2*-weighted images, and focal contrast enhancement at C1-2. In five patients there was also swelling of the spinal cord. The site of eccentric focal contrast enhancement correlated with the clinical manifestations. Follow-up imaging less than 10 months after the onset of symptoms showed no significant changes in signal intensity. Focal contrast enhancement at C1-2 remained the same in three patients, was more dense and larger in one, and less dense in another. Subsidence of swelling was seen in two patients. Atrophy of the spinal cord at C1-2, without abnormal signal and with faint contrast enhancement at C1-2 was revealed as early as 10 months after the onset of symptoms, but the contrast enhancement disappeared by 22 months. There was no correlation between clinical manifestations and spinal cord atrophy on MRI.