Brain Gray Matter Atrophy after Spinal Cord Injury: A Voxel-Based Morphometry Study

Abstract

The aim of this study was to explore possible changes in whole brain gray matter volume (GMV) after spinal cord injury (SCI) using voxel-based morphometry (VBM), and to study their associations with the injury duration, severity, and clinical variables. In total, 21 patients with SCI (10 with complete and 11 with incomplete SCI) and 21 age- and sex-matched healthy controls (HCs) were recruited. The 3D high-resolution T1-weighted structural images of all subjects were obtained using a 3.0 Tesla MRI system. Disease duration and American Spinal Injury Association (ASIA) Scale scores were also obtained from each patient. Voxel-based morphometry analysis was carried out to investigate the differences in GMV between patients with SCI and HCs, and between the SCI sub-groups. Associations between GMV and clinical variables were also analyzed. Compared with HCs, patients with SCI showed significant GMV decrease in the dorsal anterior cingulate cortex, bilateral anterior insular cortex, bilateral orbital frontal cortex (OFC), and right superior temporal gyrus. No significant difference in GMV in these areas was found either between the complete and incomplete SCI sub-groups, or between the sub-acute (duration <1 year) and chronic (duration >1 year) sub-groups. Finally, the GMV of the right OFC was correlated with the clinical motor scores of left extremities in not only all SCI patients, but especially the CSCI subgroup. In the sub-acute subgroup, we found a significant positive correlation between the dACC GMV and the total clinical motor scores, and a significant negative correlation between right OFC GMV and the injury duration. These findings indicate that SCI can cause remote atrophy of brain gray matter, especially in the salient network. In general, the duration and severity of SCI may be not associated with the degree of brain atrophy in total SCI patients, but there may be associations between them in subgroups.

Brain tissue properties and morphometry assessment after chronic complete spinal cord injury

“…Using the same technique in the very same cohort, the authors observed also myelin reduction in thalamus, cerebellum and brainstem in the same period of time (Freund et al, 2013;Grabher et al, 2015). These combined morphometry and tissue property findings in the early injury phase contrast with the absence of volume differences when comparing sub-acute (duration <1 year) and chronic (duration >1 year) patients with complete motor SCI (Chen et al, 2017).…”

“…One of the well-established methods -voxel-based morphometry (VBM), was used to monitor local grey matter volume changes following SCI to deliver conflicting results ranging from lack of SCI related brain anatomy changes (Crawley et al, 2004) to evidence about profound sensorimotor cortex reorganization (Jurkiewicz et al, 2006;Wrigley et al, 2009a;Henderson et al, 2011;Freund et al, 2013). More recent reports demonstrate grey matter loss in nonmotor areas including anterior cingulate gyrus, insula, orbitofrontal gyrus, prefrontal cortex and thalamus (Wrigley et al, 2009b;Grabher et al, 2015;Chen et al, 2017). One of the potential reasons for the reported controversial findings is the fact that these studies pooled together patients with incomplete and complete SCI (Crawley et al, 2004;Jurkiewicz et al, 2006;Chen et al, 2017) not taking into account potential impact of differences in the time span since injury (Grabher et al, 2015).…”

“…More recent reports demonstrate grey matter loss in nonmotor areas including anterior cingulate gyrus, insula, orbitofrontal gyrus, prefrontal cortex and thalamus (Wrigley et al, 2009b;Grabher et al, 2015;Chen et al, 2017). One of the potential reasons for the reported controversial findings is the fact that these studies pooled together patients with incomplete and complete SCI (Crawley et al, 2004;Jurkiewicz et al, 2006;Chen et al, 2017) not taking into account potential impact of differences in the time span since injury (Grabher et al, 2015). The non-quantitative character of the used T1-weighted MRI protocols represents another source for differences between studies.…”

Prefrontal dopaminergic system and its role in working memory and cognition in spinal cord‐injured rats

“…Spinal cord injury causes widespread structural and functional abnormalities in brain regions such as the primary motor cortex, primary somatosensory cortex, medial prefrontal cortex (PFC) and adjacent anterior cingulate cortex, causing a decrease in the volume of grey matter. Moreover, owing to the reduced volume of grey matter, structural abnormalities are observed in the corticospinal and corticopontine tracts (Chen et al., 2017).…”

“…In contrast, only a few works have focused on the possible effects of SCI on the upper nervous system, such as brain regions that control learning and memory/cognition or emotions. Although clinical evidence shows significant neurodegenerative changes, recent magnetic resonance imaging studies propose that SCI can cause investigable and vast changes in the brain (Chen et al., 2017). Recently, Wu et al.…”