MRI Grading Scale Predicts Ambulatory Function After Radiotherapy for Metastatic Spinal Cord Compression: A Prospective Single-Institution Observational Study

INTRODUCTION: Although magnetic resonance imaging (MRI) is an important modality for the diagnosis of metastatic spinal cord compression (MSCC), there are only a few reports on MSCC findings and symptoms after radiotherapy. We aimed to reveal the factors related to ambulatory function after treatment, including the MRI findings, in a prospective observational study. METHODS: Patients with suspected MSCC who were treated with radiotherapy were included in this study. Orthopedic surgeons evaluated the neurological function according to the Frankel grade. All patients underwent spinal MRI, and the degree of spinal cord compression was assessed by a radiologist and a radiation oncologist using an MRI grading scale. One month after treatment, orthopedic surgeons reassessed the Frankel grade. Twenty-three patients who were evaluated 1 month after radiotherapy were included in the analysis. RESULTS: Before radiotherapy, 17 patients were ambulatory and six were unable to walk. Furthermore, 13 patients were diagnosed with grade 3 compression on MRI (spinal cord compression with no cerebrospinal fluid seen on axial T2-weighted imaging). Patients with grade 3 MSCC were significantly more likely to be non-ambulatory at 1 month. CONCLUSIONS: The MRI grading scale for MSCC may be a prognostic factor for ambulatory function after radiotherapy. MRI findings could aid in determining the indication for radiotherapy.