Dynamics of progressive degeneration of major spinal pathways following spinal cord injury: A longitudinal study

NeuroImage: Clinical, 2023 · DOI: https://doi.org/10.1016/j.nicl.2023.103339 · Published: February 1, 2023

Spinal Cord Injury Neurology Medical Imaging

Simple Explanation

Following a spinal cord injury (SCI), damage spreads along the spinal cord, with the most significant changes occurring at the injury site. This study uses quantitative MRI to track these changes in the upper cervical cord over two years. The study focuses on anterograde (forward) and retrograde (backward) degeneration in the corticospinal tracts (CST) and dorsal columns (DC). Changes in these areas are measured using myelin-sensitive magnetization transfer saturation (MTsat) and spinal cord width. The findings reveal ongoing structural changes indicative of myelin reductions and atrophy in the CST and DC within two years after SCI. Anterograde degeneration is detectable early on, while retrograde degeneration develops over time, showing specific spatial and temporal patterns.

Study Duration

2 years

Participants

23 acute SCI patients (11 paraplegics, 12 tetraplegics) and 21 healthy controls

Evidence Level

Longitudinal study utilizing quantitative MRI

Key Findings

1
Retrograde neurodegeneration in the CST develops over time, forming a gradient towards lower cervical levels, particularly in tetraplegics.
2
Anterograde degeneration in the DC is detectable uniformly at C1-C3 early following SCI, with linear decreases in APW over time being similar across these levels.
3
The relative improvement in light touch score is associated with MTsat within the DC at baseline.

Research Summary

This study tracked the spatiotemporal dynamics of remote anterograde and retrograde spinal tract degeneration in the upper cervical cord following SCI over two years utilizing quantitative MRI. Linear rates and absolute differences in myelin-sensitive MTsat indicated retrograde and anterograde neurodegeneration in the CST and DC, respectively. Rostral and remote to the injury, the CST and DC show ongoing structural changes, indicative of myelin reductions and atrophy within 2 years after SCI.

Practical Implications

Biomarker Development

Disentangling dynamic pathological processes may provide biomarkers for regenerative and remyelinating therapies along entire spinal pathways.

Prognostication Improvement

Quantitative MRI markers can improve non-invasive prognostication, especially during early stages after injury, by combining clinical examination and MRI.

Therapeutic Targets

Understanding the distinct spatiotemporal dynamics of anterograde and retrograde degeneration can inform targeted therapeutic interventions.

Study Limitations

1
Paraplegics were significantly older than both healthy controls and tetraplegics.
2
Groups were heterogenous in terms of injury mechanism, neurological level of injury, and injury severity.
3
Final sample size was relatively small due to data exclusion in case of susceptibility and/or motion artifacts.

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury