Comparison of Acute Diffusion Tensor Imaging and Conventional Magnetic Resonance Parameters in Predicting Long-Term Outcome after Blunt Cervical Spinal Cord Injury.

This prospective longitudinal study compares the ability of conventional and diffusion tensor imaging (DTI) parameters made at the cervical spinal cord injury (CSCI) site to predict long-term neurological and functional outcomes. Twenty patients with CSCI, with follow-up at 6 or 12 months, and 15 control volunteers were included. Conventional magnetic resonance imaging (MRI) and DTI parameters were measured on admission and follow-up studies. Stepwise regression analysis was performed to find relevant parameters (normalized DTI values, conventional MRI measurements, hemorrhagic contusion [HC] or non-HC [NHC]) that correlated with three primary outcome measures: patient International Standards for Neurological Classification of Spinal Cord Injury total motor score (ISNCSCI-TMS), ability to walk, and expected recovery of upper limb motor scores (ER-ULMS) at 6 or 12 months. Univariate analysis showed HC (p < 0.0001 to 0.0098), lesion length on follow-up MRI (p < 0.0001 to 0.019), mean diffusivity (p = 0.01 to 0.045), and axial diffusivity (p = 0.004 to 0.023) predicted all three primary outcomes. Conspicuity of HC was significantly better on axial susceptibility-weighted imaging (SWI) compared with T2* images (p = 0.0009). A negative correlation existed between HC volumes on sagittal SWI images and follow-up ISNCSCI-TMS ( p = 0.02). The regression model identified NHC as the best predictor of the ability to walk (sensitivity = 88.9%; specificity = 100%; positive predictive value = 100%; negative predictive value = 91%; p < 0.0001) and lesion length on follow-up MRI as the best predictor of ER-ULMS (ß coefficient = 0.12, standard error [SE] = 0.07; R2 = 0.64; p = 0.0002). Finally, NHC (ß coefficient = 24.2, SE = 3.7; p < 0.0001) and lesion length on initial MRI (ß coefficient = 0.78, SE = 0.2; p = 0.002) were the best predictors of ISNCSCI-TMS (R2 = 0.83; p < 0.0001). Our study demonstrates HC and follow-up lesion length are potential neuroimaging biomarkers in predicting long-term neurological and functional outcome following blunt CSCI.

Diffusion Tensor Imaging Parameter Obtained during Acute Blunt Cervical Spinal Cord Injury in Predicting Long-Term Outcome.

There are no reliable neuroimaging biomarkers to predict long-term outcome after spinal cord injury. This prospective longitudinal study evaluates diffusion tensor imaging (DTI) in predicting long-term outcome after cervical spinal cord injury (CSCI). We investigate the admission DTI parameters measured in 30 patients with CSCI, with 16 of them followed up to one year, and 15 volunteers serving as controls. All magnetic resonance imaging examinations were performed within 24 h of injury. The DTI parameters were measured in patients and controls, avoiding areas of hemorrhage in patients and at corresponding upper/middle/lower regions of the spinal cord in controls. Stepwise regression analysis was performed to find relevant parameters (normalized DTI values, age, sex, hemorrhagic contusion [HC or non-HC]) that correlated with two primary outcome measures: patient International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) motor and Spinal Cord Independence Measure (SCIM III) scores at one year. Among all DTI measures, axial diffusivity (AD) most strongly correlated with both motor (r2 = 0.76, p < 0.01) and SCIM III scores (r2 = 0.77, p < 0.01) at one year. Further stepwise regression indicated that including AD (p = 0.0001) and presence of HC (p < 0.0001) in the regression model provided the best model fit for one year ISNCSCI (r2 = 0.93). The AD is a more specific parameter for axonal injury than radial diffusivity; this may indicate that axonal injury in the cord is the main factor affecting patient recovery. Our study demonstrates DTI measurement at the CSCI is a potential neuroimaging biomarker in predicting long-term neurological and functional outcome in blunt CSCI.