Diffusion Weighted MRI of Spinal Cord Injuries after Instrumented Fusion Stabilization.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is a promising technique for assessing spinal cord injury that has historically been challenged by the presence of metallic stabilization hardware. This study leverages recent advances in metal-artifact resistant multi-spectral DW-MRI to enable diffusion quantification throughout the spinal cord even after fusion stabilization. Twelve cervical spinal cord injury subjects treated with fusion stabilization and 49 asymptomatic controls underwent multi-spectral DW-MRI evaluation. Apparent diffusion coefficient (ADC) values were calculated in axial cord sections. Statistical modeling assessed ADC differences across cohorts and within distinct cord regions of the SCI subjects (at, above or below injured level). Computed mod- els accounted for subject demographics and injury characteristics. ADC was found to be elevated at injured levels compared to non-injured levels (z=3.2, p = 0.001), with ADC at injured levels decreasing over time since injury (z=-9.2, p<0.001). Below the injury level, ADC was reduced relative to controls (z=-4.4, p<0.001), with greater reductions after more severe injuries that cor- related with lower extremity motor scores (z=2.56, p=0.012). By enabling diffusion analysis near fusion hardware, the multi-spectral DW-MRI technique allowed intuitive quantification of cord dif- fusion changes after spinal cord injury both at and away from injured levels. This demonstrates the approach's potential for assessing post-surgical spinal cord integrity throughout stabilized regions.