Introduction

Spinal cord injury without fracture or dislocation (SCIWOFD) is a kind of spinal cord injury (SCI) caused by external force, but without the imaging evidence of fracture or dislocation [1,2]. The prognosis of children with SCIWOFD varies greatly among individuals, with some children showing improvement in sensory function and others showing no improvement at all [3]. Could this difference in prognosis be related to the differences in brain structure and function of children with SCI? At present, there is no research on this issue, but this study is very instructive for the prognostic prediction and advanced interfere treatment, and also has important reference value for the selection of families with different economic conditions.

Methods

57 pediatric SCIWOFD patients (age range: 6-12 years; male-to-female ratio: 6:51; ISNCSCI: 47A, 4B, 4C, 2D) were recruited in this study. We followed the patients for one year after SCIWOFD and divided them into two groups based on whether the patients had neurologic improvement (sensory scores assessed by ISNCSCI: including 27 patients without and 30 patients with neurological improvement). Images were obtained using a 3.0-T MRI system with a 12-channel phased-array head coil. High-resolution three-dimensional (3D) structural T1-weighted images were acquired for 6:59 min: repetition time (TR) / echo time (TE) / inversion time (TI) = 1800 ms / 2.13 ms / 1100 ms; flip angle (FA)=9°; number of slices=192; slice thickness=1 mm; field of view (FOV) =256× 256 mm2; matrix=256× 256; isotropic voxel size = 1×1×1 mm3. The parameters of resting-state functional magnetic resonance imaging (rs-fMRI) were acquired for 6.08 min: TR / TE = 2000 ms / 30 ms; FA=9°; number of slices=180; inter-slice gap=1 mm; slice thickness = 3 mm; FOV=220 × 220 mm2; matrix=64×64; isotropic voxel size=3.4×3.4×3.0 mm3.
Post-processing of structural and rs-fMRI data were performed using Statistical Parametric Mapping (SPM) and Data Processing Assistant for Resting-State fMRI (DPARSF) implemented in MATLAB. Independent two-sample T-test was performed to assess the GMV and fALFF differences of the whole brain between pediatric SCIWOFD patients with and without neurological improvement using SPM. Then, partial correlation analyses and ETA correlation analysis were used to explore the correlations between the GMV and fALFF values and clinical indicators. Finally, receiver operating characteristic (ROC) curve was created by plotting the true positive rate against the false positive rate.

Results

The present study characterized significant differences of GMV in right middle temporal gyrus (MTG), as well as differences of fALFF in right superior frontal gyrus, medial (SFGmed), MTG and inferior frontal gyrus, opercular part (IFGoperc) between the pediatric SCIWOFD patients with and without neurological improvement, which were partly correlated with the sensory scores and injury degree. Additionally, based on the simultaneous differences of the structure and function in right MTG, ROC analysis was performed with these two imaging measures as predictors in combination, with a relatively high sensitivity and specificity.

Discussion

We hypothesized that the pediatric SCIWOFD patients with neurological improvement had smaller GMV, which is beneficial to the control of emotion and the recovery of sensory function in later stage [4-9]. The negative correlation between the GMV values of MTG and sensory scores further confirmed our hypothesis.
Additionally, we speculated that the presence of high activation in these brain regions in pediatric SCIWOFD patients may be more conducive to the recovery of sensory function[10-16]. The positive correlation between the SFGmed and sensory scores further verified this conclusion.
The current study showed that the brain structure and function values in pediatric SCIWOFD patients were significantly correlated with the degree of injury, suggesting that brain structure and function indexes may be objective evaluation criteria for the degree of injury.
Based on the simultaneous changes of the structure and function in right MTG, the GMV and fALFF values of the right MTG were combined as predictors for a ROC analysis, suggesting that MTG, as an objective neuroimaging biomarker, may be used as a predictor of neurological improvement in pediatric SCIWOFD patients.

Conclusions

In summary, the present findings revealed significantly differences of GMV and fALFF between the pediatric SCIWOFD patients with and without neurological improvement, which were partly correlated with the sensory scores and injury degree. This suggested that the regions with brain structural and functional differences between the two groups, especially the right MTG (with differences of GMV and fALFF, simultaneously), may serve as neuroimaging biomarkers for the prediction of neurological improvement and provide image support for clinical stimulation of related brain areas in advance, so as to improve the probability of patients' neurological improvement.

Acknowledgements

The authors thank the patients who participated in this study.

References

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