Table 1.
Battery of clinical assessments for degenerative cervical myelopathy.
Table 2.
Modified Japanese Orthopedic Association (mJOA) score.
Fig 1.
A-C: T2*WI images showing mild spinal cord compression at C4-5, including: A) probabilistic SCT maps of GM (green) and WM (red) registered directly to anatomical images to calculate T2*WI WM/GM signal intensity ratio; B) baseline assessment; C) 13-month follow-up showing no change in the degree of spinal cord compression. Corresponding DTI FA maps (D-F) and MTR maps (G-I) are displayed demonstrating probabilistic WM maps (red, D, G); baseline assessments (E, H); and follow-up images (F, I). Visual inspection does not show obvious differences, but the quantitative readout (averaged over several slices) indicated progressive tissue injury including significant deterioration in composite score (t = -4.1), MTR of the rostral cord (z = -3.0), and T2*WI WM/GM of the rostral cord (z = -4.0). FA also showed a trend toward a decrease in the rostral cord (z = -2.3). CSA: cross-sectional area; DTI: diffusion tensor imaging; FA: fractional anisotropy; GM: grey matter; MTR: magnetization transfer ratio; T2*WI: T2*-weighted imaging; WM: white matter.
Table 3.
Summary of age-corrected Quantitative MRI metrics.
Table 4.
Summary of DCM patient characteristics, clinical changes, and Quantitative MRI changes at follow-up.
Fig 2.
Comparison of methods to monitor for myelopathic progression in DCM.
Top panel: The bar graph displays the fraction of subjects that are deemed to be stable (green), borderline declined (yellow), or declined (red) for each clinical and MRI method of monitoring. For mJOA, a 1-point decrease is considered borderline and ≥ 2-point decreases are considered declined. For comprehensive examinations, subjects that have 1 or 2 measures that worsen ≥ 5% are considered borderline and worsening of ≥ 3 measures is considered declined. For anatomical MRI, any new or increased compression that can be visually appreciated is considered declined. For qMRI, deterioration of ≥ 1 measure is considered declined. DCM: degenerative cervical myelopathy; mJOA: modified Japanese Orthopedic Association. Bottom panel: Diagnostic accuracy of each measure was measured as sensitivity, specificity, and Youden’s Index relative to patients’ subjective impression, which was selected as the clinical case definition.
Fig 3.
Distribution of observed changes in Quantitative MRI (qMRI) metrics at follow-up.
The observed changes in age-corrected qMRI metrics for individual subjects (displayed as Xs) are plotted in relation to the expected distribution based on the null hypothesis of no change, using test-retest reliability data to characterize the SEM and calculate z scores. The results for FARostral (top panel) are overlaid on a normal distribution. The composite score is calculated as an average of z scores for each metric, which is overlaid on a t distribution with 10 d.f.s (bottom panel). Each result is colour-coded based on the patient’s subjective impression of neurological worsening (red: worse, yellow: maybe worse, and green: the same or better). CSA: cross-sectional area; d.f.s: degrees of freedom; FA: fractional anisotropy; MCL: maximally compressed level; PDF: probability density function, SEM: standard error of measurement.
Fig 4.
Decision-making algorithm for degenerative cervical myelopathy patients initially managed non-operatively.
The decision-making algorithm requires clinical and quantitative MRI data collection at 2 time-points, and takes into account the patient’s subjective impression of worsening and objective measures of progression, including mJOA, a battery of clinical assessments, anatomical MRI, or quantitative MRI.