Evaluating the Severity and Prognosis of Acute Traumatic Cervical Spinal Cord Injury: A Novel Classification Using Diffusion Tensor Imaging and Diffusion Tensor Tractography

Abstract

Study design: Retrospective observational cohort study.

Objective: We explored the relationship between diffusion tensor imaging (DTI) parameters and prognosis in patients with acute traumatic cervical spinal cord injury (ATCSCI).

Summary of background data: DTI has been used to diagnose spinal cord injury; nevertheless, its role remains controversial.

Methods: We analyzed retrospectively 24 patients with ATCSCI who were examined using conventional T2-weighted imaging and DTI. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were recorded at the injured site. Diffusion tensor tractography (DTT) was used to measure the spinal cord white matter fiber volume (MWFV). American Spinal Injury Association (ASIA) grades were recorded. Correlations between DTI parameters and ASIA scores were evaluated using Spearman correlation coefficients.

Results: FA values at injured sites were significantly lower than those of the control group, whereas ADC values in injured and control groups were not significantly different. DTT revealed that ATCSCI could be divided into four types: Type A1-complete rupture of spinal cord white matter fiber (MWF); Type A2-partial rupture of MWF; Type B-most MWF retained with severe compression or abnormal fiber conduction direction; and Type C-MWF basically complete with slight compression. Preoperative physical examinations revealed complete injury (ASIA A) in patients with A1 (n = 4) and A2 (n = 4). The ASIA grades or scores of A2 were improved to varying degrees, whereas there was no significant improvement in A1. FA values and MWFV of ASIA B, C, and D were significantly higher than those of ASIA A. FA and MWFV were correlated with ASIA motor score preoperatively and at final follow-up.

Conclusion: We propose a classification for the severity of ATCSCI based on DTI and DTT that may explain why some patients with ASIA A recover, whereas others do not.Level of Evidence: 4.