Specific Brain Morphometric Changes in Spinal Cord Injury: A Voxel-Based Meta-Analysis of White and Gray Matter Volume

The objective of the study was to investigate degenerative changes of white matter volume (WMV) and gray matter volume (GMV) in individuals after a spinal cord injury (SCI). Published studies of whole-brain voxel-based morphometry (VBM) published between January 1, 2006 and March 1, 2018 comparing SCI patients with controls were collected by searching PubMed, Web of Science, and EMBASE databases. Voxel-wise meta-analyses of GMV and WMV differences between SCI patients and controls were performed separately using seed-based d mapping. Twelve studies with 12 GMV data sets and 9 WMV data sets yielded a total of 466 individuals (190 SCI patients and 276 controls) who were included in this meta-analysis. Compared with controls, SCI patients showed GMV atrophy in sensorimotor system regions including the bilateral sensorimotor cortex (S1 and M1), the supplementary motor area (SMA), paracentral gyrus, thalamus, and basal ganglia, as well as WMV loss in the corticospinal tract.GMV aberrancies were also demonstrated in brain regions responsible for cognition and emotion, such as the orbitofrontal cortex (OFC) and the left insula. Additionally, GMV in both the bilateral S1 and the left SMA was positively correlated with the time span after the injury. In conclusion, anatomical atrophy in cortical-thalamic-spinal pathways suggested that SCIs may result in degenerative changes of the sensorimotor system. Further, OFC and insula GMV abnormalities may explain symptoms such as neuropathic pain and potential cognitive-emotional impairments in chronic SCI patients. These findings indicate that anatomical brain magnetic resonance imaging (MRI) protocols could be neuroimaging biomarkers for interventional studies and treatments.