Introduction: The objective of the current study is to quantitatively assess MR imaging and determine its role in predicting surgical outcome in patients with cervical spondylotic myelopathy (CSM).
Methods: Two hundred and seventy patients diagnosed with CSM were enrolled in the prospective multicenter North American study. Of these, 80 patients had full outcome data at 1-year follow up along with MRIs that could be analyzed. A signal change ratio (SCR) was formulated by measuring signal change at the site of suspected pathology against two baseline references (C2/C7). Using disjoint cluster analysis, patients were divided into three groups based on ratio. MRIs were also evaluated for the presence/absence of signal intensity (SI) change and categorized into class 0 (normal-T1/normal-T2), 1 (normal-T1/high-T2) and 2 (low-T1/high-T2). ANOVA was used to compare demographic and outcome (1-year mJOA) differences across groups and classes.
Results: SCR categorized into 3 groups: (1), x<1.20(n=34); (2), 1.20=x<1.55(n=30); and (3), x=1.55(n=16). Patients in group 3 presented with positive Babinski sign, hyperreflexia and corticospinal motor deficits more frequently than those in group 1. SI differed significantly across the three groups: zero patients in group 3 had normal-T1/normal-T2, whereas zero patients in group 1 had low-T1/high-T2 SI. Transverse area was significantly larger in group 1 (mean=49.8) than in 3 (mean=40.1) and was smaller in class 2 (mean=40.0) and class 1 (mean=42.3) compared to class 0 (mean=51.8). Finally, SCR was 1.10, 1.33 and 1.6 in class 0, 1 and 2, respectively, with all comparisons reaching statistical significance. There were no differences between the three classes or groups with respect to outcome at 1-year (mJOA).
Conclusions: Our novel measurement technique has allowed us to objectively assess SI on T2 imaging and relate these findings to baseline clinical presentations and outcome. This information strengthens the role of MRI as a diagnostic tool and aids in stratifying severity of disease.
Patient Care: Increased understanding of the significance of MRI signal change and how it can be quantified will aid in diagnosing CSM patients and help determine the severity of disease. The signal change ratio discussed in our research also presents a novel way in which MRI signal change can be assessed and therefore will directly impact clinical decision-making.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Have a better understanding of the significance of MR signal changes in patients with CSM, 2) Appreciate the value of quantitative assessment of MR imaging in CSM patients