Clinical Significance of 3D-MRI/18F-FDG PET Fusion Imaging of Patients with Cervical Compressive Myelopathy

Abstract

The present study was designed to evaluate the use of three-dimensional (3D)-MRI/18F-FDG PET fusion imaging to define intramedullary signal changes on MRIs and local glucose metabolic rate measured on 18F-FDG PET in relation to clinical outcome and prognosis. Quantitative analysis of intramedullary signal changes on MRIs included calculation of the signal intensity ratio (SIR). On fusion images, the maximal count at the lesion was adopted as the standardized uptake value (SUVmax). The SUV ratio (SUVR) was also calculated. Neurological assessment was conducted using the Japanese Orthopaedic Association (JOA) scoring system. The SIR on T1-weighted images (WIs), but not SIR on T2-WIs, correlated with preoperative JOA score and postoperative neurological improvement. Lesion-SUVmax correlated with SIR on T1-WIs, but not with SIR on T2-WIs, and also with postoperative neurological outcome. The SUVR correlated better than SIR on T1-WIs and lesion-SUVmax with neurological improvement. Longer symptom duration correlated negatively with SIR on T1-WIs, positively with SIR on T2-WIs, and negatively with SUVmax. Our results suggest that low-intensity signal on the T1-WIs correlates with poor postoperative neurological outcome. SUVmax measured at lesions with increased signal intensity and SUVR measured on fusion MRI/PET are sensitive parameters for prediction of clinical outcome.