Neurological improvement associated with resolution of irradiation-induced myelopathy: serial magnetic resonance imaging and positron emission tomography findings.

We document serial magnetic resonance imaging (MRI) and [(18)F] 2-fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) findings in the process of improvement from delayed radiation necrosis of the spinal cord. A 61-year-old woman underwent radiotherapy for an oral carcinoma. Forty-six months later she developed a left-sided Brown-Séquard syndrome, suggesting incomplete cervical cord transection below the cervico-thoracic junction. Two months after starting steroid therapy, she had gradual clinical improvement, which continues 8 years after the termination of radiotherapy. Neurological improvement was associated with gradual resolution of an extensive high-intensity area within the cervico-thoracic spinal cord on MRI. Initially, the FDG-PET showed linear and uniform increase in FDG uptake throughout the cervical spinal cord with standardized uptake value of 2.68 +/- 0.16 (mean +/- SD), but it returned to normal value (1.90 +/- 0.14) at final follow-up. Considering that the normalization of FDG uptake correlated with neurological recovery, the uniform- and diffuse-increased FDG uptake noted in the initial course of myelopathy could reflect the metabolic activity of the compromised spinal cord.