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 [18F] 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.