Correlations between preoperative diffusion tensor imaging and surgical outcome in patients with cervical spondylotic myelopathy

Abstract

Objective: To investigate the correlations between preoperative diffusion tensor imaging (DTI), a Magnetic Resonance Imaging (MRI)-based technique and surgical outcome in patients with cervical spondylotic myelopathy (CSM).

Methods: A retrospective study of 95 patients with CSM who received diagnosis and surgical treatment in our hospital was carried out. According to the recovery rate of the Japanese Orthopaedic Association (JOA) scale at the 1-year postoperative follow-up, the patients were divided into a good recovery group (JOA recovery rate ≥60%, n = 47) and a poor recovery group (JOA recovery rate <60%, n = 48). Patients in both groups underwent diffusion tensor imaging examination before surgery. The preoperative fractional anisotropy (FA) value, apparent diffusion coefficient (ADC) value, longitudinal dispersion (AD) rate, and lateral dispersion (VD) rate were compared between the two groups. Pearson correlation coefficient was used to analyze the correlation between the preoperative DTI quantization parameters (FA, ADC, AD, VD) and the postoperative JOA recovery rate. In addition, we compared the preoperative spinal cord compression ratio (CR), spinal cord cross-sectional area (TA), maximum spinal cord compression (MSCC), and maximum canal compromise (MCC) between the above two groups. The correlations between the four measurements and the postoperative JOA recovery rate were analyzed using Pearson correlation coefficient.

Results: The preoperative FA value in the good recovery group was significantly higher than that in the poor recovery group, while the ADC value was significantly lower (both P<0.001). The good recovery group had lower preoperative AD and VD, but there was no statistical significance (both P>0.05). Pearson correlation analysis showed that the preoperative FA value was positively correlated with the JOA recovery rate (P<0.05), while the VD value had significantly negative correlation with the JOA recovery rate (P<0.05). The preoperative ADC and AD values were negatively correlated with JOA recovery rate, whereas there was no statistical significance (both P>0.05). The CR, TA, MSCC and MCC values measured before surgery in the good recovery group were significantly lower than those in the poor recovery group (all P<0.001); were negatively correlated with the JOA recovery rate (all P<0.05), while the correlation with TA was not statistically significant (P>0.05).

Conclusion: DTI can evaluate the severity of the patient's condition before surgery by analyzing the subtle structural changes in patients with CSM. At the same time, the preoperative FA, VD, CR, MSCC, and MCC values are all associated with the surgery efficacy, which paves the way for the next step of clinical treatment.

Keywords: Diffusion tensor imaging; Japanese orthopaedic association recovery rate; cervical spondylotic myelopathy; correlation; fractional anisotropy.

Figure 1

Comparison of typical MRI of two groups before and after surgery. A-D: Sagittal preoperative and postoperative T2-weighted images, axial preoperative and postoperative T2-weighted images in the poor recovery group, respectively; E-H: Sagittal preoperative and postoperative T2-weighted images, axial preoperative and postoperative T2-weighted images in the good recovery group, respectively. MRI: magnetic resonance imaging.

Figure 2

Quantitative parameters of preoperative DTI in the poor recovery group. A-D: Preoperative FA, ADC, AD, and VD images in the poor recovery group, respectively. DTI: diffusion tensor imaging; FA: fractional anisotropy; ADC: apparent diffusion coefficient; AD: longitudinal dispersion; VD: lateral dispersion.

Figure 3

Quantitative parameters of preoperative DTI in the good recovery group. A-D: Preoperative FA, ADC, AD, and VD images in the good recovery group, respectively. DTI: diffusion tensor imaging; FA: fractional anisotropy; ADC: apparent diffusion coefficient; AD: longitudinal dispersion; VD: lateral dispersion.

Figure 4

Pearson correlation analysis between the preoperative DTI quantitative values and the postoperative JOA recovery rate. A: Pearson correlation analysis between preoperative FA and postoperative JOA recovery rate; B: Pearson correlation analysis between preoperative ADC and postoperative JOA recovery rate; C: Pearson correlation analysis between preoperative AD and postoperative JOA recovery rate; D: Pearson correlation analysis between preoperative VD and postoperative JOA recovery rate. DTI: diffusion tensor imaging; FA: fractional anisotropy; ADC: apparent diffusion coefficient; AD: longitudinal dispersion; VD: lateral dispersion; JOA: Japanese Orthopaedic Association.

Figure 5

Pearson correlation analysis of preoperative CR, TA, MSCC and MCC values and postoperative JOA improvement rate. A: Pearson correlation analysis between FA and postoperative JOA recovery rate; B: Pearson correlation analysis between ADC and postoperative JOA recovery rate; C: Pearson correlation analysis between AD and postoperative JOA recovery rate; D: Pearson correlation analysis between VD and postoperative JOA recovery rate. CR: compression ratio; TA: cross-sectional area; MSCC: maximum spinal cord compression; MCC: maximum canal compromise; FA: fractional anisotropy; ADC: apparent diffusion coefficient; AD: longitudinal dispersion; VD: lateral dispersion; JOA: Japanese Orthopaedic Association.