High-resolution magnetic resonance imaging and 18FDG-PET findings of the cervical spinal cord before and after decompressive surgery in patients with compressive myelopathy

STUDY DESIGN.: Evaluation of cervical spinal cord (CSC) of patients with compressive myelopathy by magnetic resonance imaging (MRI) and high-resolution (F)fluoro-deoxyglucose (FDG) positron emission tomography (PET). OBJECTIVE.: To determine changes in morphology, intramedullary signal intensity, and glucose metabolic rate in CSC after decompression, and to assess the utility of FDG-PET in evaluation of patients with cervical myelopathy. SUMMARY OF BACKGROUND DATA.: The significance of CSC enlargement after decompression and signal intensity changes within the cord remain elusive. No data are available on metabolic activity of the compressed CSC. Only a few studies have examined correlation between high-resolution MRI and FDG-PET neuroimaging in cervical myelopathy. METHODS.: We studied 24 patients who underwent cervical decompressive surgery in terms of postoperative neurologic improvement and changes in MRI and FDG-PET. Neurologic status was assessed by the Japanese Orthopedic Association scoring system (17-point scale). Signal intensity change in the cord was qualitatively assessed on both T1- and T2-weighted images. The transverse area of the CSC on MRIs and glucose metabolic rate (standardized uptake value [SUV]) from FDG-PET were measured digitally. RESULTS.: Neurologic improvement correlated with preoperative CSC transverse area at maximal compression (P < 0.01) and at follow-up (P < 0.001) and with mean SUV before surgery (P < 0.01) and at follow-up (P < 0.05). Preoperative signal intensity change on MRIs (low intramedullary signal intensity abnormality on T1-weighted image and high intramedullary on T2-weighted image) correlated negatively with neurologic improvement rate (P < 0.05). The transverse area of the CSC was significantly smaller after surgery in patients with preoperative MRI signal intensity changes (P < 0.05). The SUV at follow-up tended to normalize in association with neurologic improvement. CONCLUSION.: Our results showed that postoperative neurologic improvement in patients with cervical compressive myelopathy correlated with increased transverse area of the spinal cord, signal intensity change on both T1- and T2-weighted image, and the mean SUV. © 2009, Lippincott Williams & Wilkins.