Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine

CNS Neurosci Ther, 2019 · DOI: 10.1111/cns.13044 · Published: January 1, 2019

Spinal Cord Injury Neurology Veterinary Medicine

Simple Explanation

This study investigates the degeneration of white and gray matter in canine spinal cord injury (SCI) models using diffusion tensor imaging (DTI). DTI is an advanced MRI technique that visualizes and quantifies the microstructure of fiber bundles. The study found that after SCI, fractional anisotropy (FA) values, which correlate with myelin integrity and fiber density, significantly decreased in the lesion epicenter and caudal segments. Apparent diffusion coefficient (ADC) values, reflecting water molecule displacement, initially decreased and then increased in the lesion epicenter and caudal segments. Pathological examination confirmed the dynamic changes observed in DTI parameters, supporting the potential of DTI as a tool for assessing spinal cord degeneration after injury.

Study Duration

12 weeks

Participants

12 healthy female Beagles (5 controls, 7 SCI models)

Evidence Level

Not specified

Key Findings

1
Fractional anisotropy (FA) values significantly decreased in the lesion epicenter and caudal segments after SCI, indicating disruption of fiber bundle integrity.
2
Apparent diffusion coefficient (ADC) values initially decreased and then increased in the lesion epicenter and caudal segments, suggesting edema and hematoma formation in the acute phase followed by gradual improvement.
3
White matter degeneration was more pronounced in the caudal segments compared to the rostral segments, indicating an asymmetrical degeneration pattern after SCI.

Research Summary

This study aimed to investigate the degeneration of white matter and gray matter and pathological mechanism in canine after SCI. Diffusion tensor imaging (DTI) was performed on canine models with normal (n = 5) and injured (n = 7) spinal cords using a 3.0T MRI scanner at precontusion and 3 hours, 24 hours, 6 weeks, and 12 weeks postcontusion. Diffusion tensor imaging is more sensitive to degeneration of white matter than gray matter, and the white matter degeneration may be not symmetrical which meant the caudal degradation appeared to be more severe than the rostral one.

Practical Implications

Treatment Strategies

Findings may inform the development of targeted therapies to inhibit axonal injury and promote nerve tissue preservation after SCI.

Prognostic Tool

DTI could serve as a valuable tool for predicting long-term functional recovery following SCI.

Canine Model Relevance

Further research using the canine model is warranted due to its translational relevance to human SCI.

Study Limitations

1
Respiratory rate and heart rate under anesthesia may affect MRI signal acquisition.
2
Relatively low spatial resolution of DTI influenced by partial volume effects.
3
Not specified

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