Tract-specific magnetization transfer ratio provides insights into the severity of degenerative cervical myelopathy

Study design

Cross-sectional study.

Objectives

This study’s goal is to report whether Magnetization Transfer Ratio (MTR) can evaluate the severity of white matter (WM) injury in degenerative cervical myelopathy (DCM).

Setting

Laureate Institute of Brain Research, USA; Department of Neurosurgery, University of Oklahoma Health Sciences Center, USA.

Methods

27 DCM patients were aged-matched with 20 healthy controls (HC) and categorized into treatment groups based on modified Japanese Orthopedic Association (mJOA) severity (11 mild and 16 moderate/severe). Regional and tract MTRs were extracted from the two vertebral levels containing maximum compression within magnetization transfer images. MTR differences between groups were assessed using a one-way ANOVA or Kruskal-Wallis test. The association between MTR and mJOA measures was evaluated using Spearman’s correlation.

Results

Significant decreases in MTR were found between HC and moderate/severe groups in the overall (p = 0.0065) and ventral (p = 0.0009) WM regions; and ventral corticospinal (p = 0.0101), ventral reticulospinal (p = 0.0084), spinal lemniscus (p = 0.0079), and fasciculus cuneatus (p = 0.0219) tracts. The spinal lemniscus MTR also significantly decreased between HC and mild groups (p = 0.038). Ventral reticulospinal tract MTR correlated with upper (r = 0.439; p = 0.022) and lower (r = 0.386; p = 0.047) limb motor mJOA scores.

Conclusions

Significant tract-based MTR changes and correlations align with known DCM symptoms, are demonstrated to be lost at the regional level, and display the inhomogeneous compressive damage occurring within DCM spinal cords.