Imaging Criterion for Responsibility Segment of Cervical Myelopathy

Bolong Zheng, Dingjun Hao, Zhen Chang and Baorong He

Department of Spine Surgery, Xi’an Jiaotong University, China

^*Correspondance to: Zhen Chang and Baorong He 

 PDF  Full Text DOI: 10.25107/2474-1647.2411

Abstract

Purpose: Explore the most appropriate combination of four MRI parameters (signal intensity on T2WI, cord/dura sagittal ratio, cord/dura area ratio, cord deformation ratio) as the imaging criterion for cervical myelopathy to achieve the highest sensitivity and specificity. Material and
Methods: From February 2011 to August 2013, One hundred and thirty patients with single segmental cervical myelopathy were chosen from the patient data base of our hospital, male/ female ratio was 11/9, the average age was 48.62 ± 10.02 years (ranged 37~54 years), the average course of disease was 6.51 ± 4.33 months (ranged 4.1~10.2 months). Through measuring the preoperative MRI images with PACS software, the cut-off points of signal intensity on T2WI, cord/ dura sagittal ratio, cord/dura area ratio, cord deformation ratio were calculated respectively using 100 patients according to Receiver Operating Characteristic (ROC). After testing the effectiveness of these four cut-off points, the most appropriate combination of these four parameters as the imaging criterion of cervical myelopathy was explored by the rest 30 patients through calculate the sensitivity, specificity and Youden index of each possible combination.
Results: The cut-off points of signal intensity on T2WI, cord/dura sagittal ratio, cord/dura area ratio and cord deformation ratio were 1, 0.77, 0.61 and 0.46 respectively according to Receiver Operating Characteristic (ROC), and Youden index of these four cut-off points were 0.72, 0.67, 0.63 and 0.48, respectively, with all in acceptable range. Through comparing each possible combination with one another, the most appropriate combination was: T2WI ≥ 1 or (cord/dura sagittal ratio ≥ 0.77 and cord/dura area ratio ≥ 0.61 and cord deformation ratio ≤ 0.46), with corresponding sensitivity =0.97, specificity =0.89, Youden index =0.86, PPV (Positive Predictive Value) =0.74, NPV (Negative Predictive Value) =0.99, showing a satisfying diagnostic imaging criterion for cervical myelopathy.
Conclusion: When using T2WI ≥ 1 or (cord/dura sagittal ratio ≥ 0.77 and cord/dura area ratio ≥ 0.61 and cord deformation ratio ≤ 0.46) as the diagnostic imaging criterion of cervical myelopathy, the sensitivity and the specificity are both high. It’s a useful assistant tool for spine surgeons better decide the responsibility segment and boost the accuracy of surgical decompression, but the scope of application should be evaluated prudently.

Keywords

Cervical myelopathy; Responsibility segment; Diagnostic test; Youden index; ROC curve

Cite the article

Zheng B, Hao D, Chang Z, He B. Imaging Criterion for Responsibility Segment of Cervical Myelopathy. Clin Surg. 2019; 4: 2411.