Introduction: Fractional anisotropy (FA) of the high cervical cord (C1-C2), rostral to the injury site, correlates with upper limb function in patients with chronic cervical spinal cord injury (SCI). In acute cervical SCI, this relationship has not been investigated. The purpose of this study was to identify functional correlates of FA of the high cervical cord, above the level of a traumatic lesion, in a series of acute cervical SCI patients.
Methods: This retrospective study was performed on patients with traumatic cervical SCI who underwent pre-surgical cervical spinal cord DTI at our institution. FA of the whole cord as well as the lateral corticospinal tracts (CST) was calculated on axial images from C1-C2 (Figure 1). Upper limb motor (C5-T1) and sensory function (C2-T1) scores were extracted from the admission ASIA exams. Correlation analysis for FA with ASIA scores was performed using Pearson’s correlation. Statistical significance was set at p<0.05.
Results: Twelve subjects (9 men, 3 women, mean age 54.7±4.0) were included in this study. No patient had cord compression or intramedullary T2-weighted hyperintensities rostral to the C2-C3 disc space. Cervical spinal cord DTI was performed at a mean duration of 3.6±0.9 days post-injury. For the C1-C2 segments, the mean FA of the whole cord was 0.61±0.01 and for the CST was 0.67±0.01. FA correlated with upper limb motor score (whole cord: r=0.59, p=0.04; CST: 0.67, p=0.01) and the ASIA score (whole cord: r=0.61, p=0.03; CST: r=0.71, p=0.009). No correlation was found between FA and sensory scores.
Conclusions: FA of the whole cervical cord as well as the CST, rostral to the injury site, is associated with preserved upper limb motor function as well as superior ASIA grades after acute cervical SCI. FA of the high cervical cord is a potential biomarker of neural injury after acute cervical SCI.
Patient Care: This abstract provides surgeons with preliminary data on prognostic value of high cervical diffusion tensor imaging after acute cervical spinal cord injury. We hope this will enable other investigators to apply this technique to characterize the clinical value of diffusion tensor imaging in patients with acute spinal cord injury.
Learning Objectives: 1. Understand that high cervical DTI, rostral to the injury site, is a potential non-invasive biomarker for acute cervical spinal cord injury.
2. Recognize that DTI metrics, such as fractional anisotropy, provide an estimate of spinal cord microstructure as well as function in subjects with acute cervical spinal cord injury.
3. Identify advantages of high cervical DTI, remote from the injury site, in clinical imaging studies for cervical spinal cord injury.