Clinical significance of MRI/18F-FDG PET fusion imaging of the spinal cord in patients with cervical compressive myelopathy

Purpose 18F-FDG PET is used to investigate the metabolic activity of neural tissue. MRI is used to visualize morphological changes, but the relationship between intramedullary signal changes and clinical outcome remains controversial. The present study was designed to evaluate the use of 3-D MRI/18F-FDG PET fusion imaging for defining intramedullary signal changes onMRI scans and local glucose metabolic rate measured on 18F-FDG PET scans in relation to clinical outcome and prognosis. Methods We studied 24 patients undergoing decompressive surgery for cervical compressive myelopathy. All patients underwent 3-D MRI and 18F-FDG PET before surgery. Quantitative analysis of intramedullary signal changes on MRI scans included calculation of the signal intensity ratio (SIR) as the ratio between the increased lesional signal intensity and the signal intensity at the level of the C7/T1 disc. Using an Advantage workstation, the same slices of cervical 3-D MRI and 18F-FDG PET images were fused. On the fused images, the maximal count of the lesion was adopted as the standardized uptake value (SUV max). In a similar manner to SIR, the SUV ratio (SUVR) was also calculated. Neurological assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. Results The SIR on T1-weighted (T1-W) images, but not SIR on T2-W images, was significantly correlated with preoperative JOA score and postoperative neurological improvement. Lesion SUVmax was significantly correlated with SIR on T1-W images, but not with SIR on T2-W images, and also with postoperative neurological outcome. The SUVR correlated better than SIR on T1-W images and lesion SUVmax with neurological improvement. Longer symptom duration was correlated negatively with SIR on T1-W images, positively with SIR on T2-W images, and negatively with SUVmax. Conclusion Our results suggest that low-intensity signal on T1-W images, but not on T2-W images, is correlated with a poor postoperative neurological outcome. SUVmax of lesions showing increased signal intensity and SUVR measured on fusion MRI/PET scans are more sensitive parameters for predicting clinical outcome than signal intensity on the MRI scan

Use of multivariate linear regression and support vector regression to predict functional outcome after surgery for cervical spondylotic myelopathy

This study introduces the use of multivariate linear regression (MLR) and support vector regression (SVR) models to predict postoperative outcomes in a cohort of patients who underwent surgery for cervical spondylotic myelopathy (CSM). Currently, predicting outcomes after surgery for CSM remains a challenge. We recruited patients who had a diagnosis of CSM and required decompressive surgery with or without fusion. Fine motor function was tested preoperatively and postoperatively with a handgrip-based tracking device that has been previously validated, yielding mean absolute accuracy (MAA) results for two tracking tasks (sinusoidal and step). All patients completed Oswestry disability index (ODI) and modified Japanese Orthopaedic Association questionnaires preoperatively and postoperatively. Preoperative data was utilized in MLR and SVR models to predict postoperative ODI. Predictions were compared to the actual ODI scores with the coefficient of determination (R(2)) and mean absolute difference (MAD). From this, 20 patients met the inclusion criteria and completed follow-up at least 3 months after surgery. With the MLR model, a combination of the preoperative ODI score, preoperative MAA (step function), and symptom duration yielded the best prediction of postoperative ODI (R(2) = 0.452; MAD = 0.0887; p = 1.17 × 10(−3)). With the SVR model, a combination of preoperative ODI score, preoperative MAA (sinusoidal function), and symptom duration yielded the best prediction of postoperative ODI (R(2) = 0.932; MAD = 0.0283; p = 5.73 × 10(−12)). The SVR model was more accurate than the MLR model. The SVR can be used preoperatively in risk/benefit analysis and the decision to operate

Is there a benefit to operating on patients (bedridden or in wheelchairs) with advanced stage cervical spondylotic myelopathy?

Surgical treatment of cervical spondylotic myelopathy (CSM) aims to prevent or delay the progression of the disease. Many patients are diagnosed in advanced stages of the disease, presenting severe functional disability and extensive radiologic changes, which suggests clinical irreversibility. There are doubts about the real benefit of surgery in patients who are seriously ill, bedridden or in a wheelchair. The objective of the study is to evaluate the effects of surgical treatment in the clinical outcomes of patients severely affected by CSM. We analyzed patients with CSM who received an operation at a single institution between 1996 and 2008. Cases with a preoperative Nurick score equal to 5 were studied. We describe postoperative clinical improvement and compare the demographics and clinical data between the patients who improved and those who had no improvement. Radiological findings were also analyzed. We evaluated 55 patients operated on. Nine presented with preoperative Nurick score of 5 (16.3%). The mean age was 69.77 ± 6.6 years (95% CI 64.65–79.90). The mean follow-up was 53.44 ± 35.09 months (CI 26.46–80.42). Six patients (66.6%) achieved functional improvement when assessed by the Nurick scale, regaining the ability to walk. All patients improved on the JOAm scale, except one. The mean preoperative Nurick score was 5, while the mean postoperative Nurick score was 4.11 ± 0.92 (95% CI 3.39–4.82) (Wilcoxon p = 0.027). The mean preoperative JOAm score was 6.4, and postoperative was 9.88 ± 2.31 (CI 95% 8.10–11.66) (Wilcoxon p = 0.011). All spinal cords presented high-intensity signal on T2-weighted images. There was no correlation between the number of spinal cord high-intensity signal levels and clinical improvement. Three out of seven patients (whose image was adequate for analysis) had evident spinal cord atrophy, and two of them did not improve clinically. In the whole sample of patients, the mean length of disease for those who improved was 9.25 ± 7.31 months (95% CI 1.56–16.93), and for those who did not improve was 38.00 ± 19.28 months (95% CI 9.91–85.91) (Mann–Whitney p = 0.02). In conclusion, two-thirds of patients with CSM Nurick scores of 5 who were either bedridden or in wheelchairs at the time of diagnosis improved at least one degree on the Nurick scale after surgical treatment, thus returning to walking. The JOAm scale was more sensitive to clinical changes than the Nurick scale. Patients with longer lengths of disease had worse outcomes