A New Multi-Parametric MRI-Based Scoring System for Degenerative Cervical Myelopathy: The Severity on Imaging Myelopathy Score (SIMS)

Abstract

Background/Objectives: Degenerative cervical myelopathy (DCM) is the leading cause of functional disabilities of spinal origin in people over 50 years old. The objective of the present study was to establish a multi-parametric weighted scoring system that is easy to use in daily practice, based on the most significant MRI signs and correlated as strongly as possible with the clinical presentation (mJOA)-we call this system the SIMS or Severity on Imaging Myelopathy Score. Methods: Ninety-nine patients who underwent clinical and radiological evaluation by mJOA and MRI between January 2015 and March 2021 were retrospectively included. The variables included in the score were the Fujiwara ratio, the T2-weighted intramedullary hyperintensity, the aspect of the peri-medullary fluid cisterns, the Torg-Pavlov ratio, the local kyphosis and the number of stenotic levels. Each variable was first correlated to the mJOA score for each patient, making it possible to construct the final SIMS at the end, and validate it by comparison with mJOA scores. Results: The variables that were significantly correlated with one another were the T2-weighted intramedullary hyperintensity, the reduction in peri-medullary fluid spaces and the number of stenotic levels (p < 0.05). Then, points were assigned to each variable according to their relative importance and made it possible to construct the definitive SIMS. The final Spearman correlation coefficient between the SIMS and the mJOA score was -0.747. Conclusions: This work showed that this new multi-parametric MRI-based scoring system represents a consistent means to characterize the degree of severity of degenerative cervical myelopathy.

Keywords: MRI; SIMS; cervical spondylotic myelopathy; increased signal intensity.

Figure 1

FR measured, respectively, at 0.55 (A), 0.44 (B), 0.37 (C) and 0.20 (D).

Figure 2

(A) No T2HI; (B) focal T2HI; (C) multifocal T2HI.

Figure 3

(A): CSF visible anteriorly and posteriorly; (B) CSF erased anteriorly or posteriorly; (C) CSF erased anteriorly and posteriorly but root cisterns visible; (D) totally erased cisterns.

Figure 4

Example of measurement of the TPR. (A) TPR = 0.85; (B) TPR = 0.75; (C) TPR = 0.59.

Figure 5

Example of measurement of the local angle. (A) LK = 2.2°; (B) LK = 6.A°.

Figure 6

Relationship between the mJOA score and the FR (A); the TPR (B) and the LK (C). A dot represents a single patient, a line 2 patients, a helix 3 patients and a cross 4 patients

Figure 7

Relationship between the SIMS and the mJOA. A dot represents a single patient, a line 2 patients, a helix 3 patients and a cross 4 patients