Application of Neurite Orientation Dispersion and Density Imaging to Evaluate and Predict the Surgical Outcome for Degenerative Cervical Myelopathy

Objectives Although the neurite orientation dispersion and density imaging (NODDI) has been shown useful to evaluate the spinal cord dysfunction, there are few prospective studies on analyzing the operation recovery of degenerative cervical myelopathy (DCM) disease using NODDI. This study aims to investigate the preoperative evaluation and predictive ability of NODDI in DCM patients who received posterior cervical laminoplasty. Methods This prospective study included 55 patients with DCM from January to December 2017. NODDI metrics, including intracellular volume fraction (Vic), isotropic volume fraction (Viso), and orientation dispersion index (ODI) were measured at the maximally compressed (MC) level and the non-compressed C2 level in each patient at the preoperative and the 3- and 6-month postoperative follow-up stages. Neurological function was assessed using the modified Japanese Orthopaedic Association (mJOA) scoring system at each stage. Spearman's correlation and Kendall's tau-b correlation were used to analyze the relationship between NODDI metrics and mJOA scores. Wilcoxon signed rank test was used to examine the changes in the NODDI and mJOA scores between the preoperative and 6-month follow-up stages. ROC analysis was used to further evaluate the predictive capability. Results Preoperative Vic at the level of C2 has a significant correlation with the preoperative mJOA score (r = 0.278, p = 0.048). Vic and Viso at the MC level were significantly different between the preoperative period and 6-month follow-up. Viso at the MC level was correlated with the mJOA score at 6-month follow-up (r = -0.302, p = 0.044). Vic and ODI at the C2 level predicted the surgical prognosis, with areas under the receiver-operating characteristic curve of 0.663 (p = 0.042) and 0.716 (p = 0.014). Conclusions The preoperative NODDI metrics at the C2 level are capable of evaluating the severity of spinal cord dysfunction and predict the surgical outcome.