Diffusion Tensor Imaging to Assess Injury Severity in Rabbits With Acute Spinal Cord Injury

Area of Science:

• Neuroimaging
• Spinal Cord Injury Research
• Biomedical Engineering

Background:

• Assessing spinal cord injury (SCI) severity and recovery using diffusion tensor imaging (DTI) metrics remains controversial.
• Understanding the sensitivity of DTI metrics in different phases of SCI is crucial for effective treatment and management.

Purpose of the Study:

• To evaluate the sensitivity of DTI metrics, specifically fractional anisotropy (FA) and average dispersion coefficient (DCavg), for assessing damage severity and functional recovery following acute SCI.
• To compare the utility of DCavg and FA in quantitatively measuring SCI and predicting functional outcomes.

Main Methods:

• A rabbit model of graded contusion SCI was established using varying balloon catheter volumes.
• Serial magnetic resonance imaging (MRI) scans were performed to measure intramedullary lesion length (IMLL) and DTI metrics (FA, DCavg).
• Behavioral and histological assessments were used to evaluate damage severity and functional recovery.

Main Results:

• DCavg and FA were significantly reduced post-SCI, indicating tissue damage.
• DCavg demonstrated significant differences between moderate and severe injury groups across multiple time points, correlating with behavioral and histological outcomes.
• FA showed limited correlation with functional recovery and damage severity, suggesting lower sensitivity in the acute phase.

Conclusions:

• Average dispersion coefficient (DCavg) derived from DTI is a sensitive metric for quantitatively evaluating damage severity and indicating functional recovery in acute spinal cord injury (SCI).
• Fractional anisotropy (FA) may not be a sensitive indicator for assessing damage and recovery during the acute phase of SCI.
• DTI metrics, particularly DCavg, hold potential for objective assessment in SCI research and clinical practice.