Voxel-based analysis of grey and white matter degeneration in cervical spondylotic myelopathy

Abstract

In this prospective study, we made an unbiased voxel-based analysis to investigate above-stenosis spinal degeneration and its relation to impairment in patients with cervical spondylotic myelopathy (CSM). Twenty patients and 18 controls were assessed with high-resolution MRI protocols above the level of stenosis. Cross-sectional areas of grey matter (GM), white matter (WM), and posterior columns (PC) were measured to determine atrophy. Diffusion indices assessed tract-specific integrity of PC and lateral corticospinal tracts (CST). Regression analysis was used to reveal relationships between MRI measures and clinical impairment. Patients showed mainly sensory impairment. Atrophy was prominent within the cervical WM (13.9%, p = 0.004), GM (7.2%, p = 0.043), and PC (16.1%, p = 0.005). Fractional anisotropy (FA) was reduced in the PC (−11.98%, p = 0.006) and lateral CST (−12.96%, p = 0.014). In addition, radial (+28.47%, p = 0.014), axial (+14.72%, p = 0.005), and mean (+16.50%, p = 0.001) diffusivities were increased in the PC. Light-touch score was associated with atrophy (R2 = 0.3559, p = 0.020) and FA (z score 3.74, p = 0.003) in the PC, as was functional independence and FA in the lateral CST (z score 3.68, p = 0.020). This study demonstrates voxel-based degeneration far above the stenosis at a level not directly affected by the compression and provides unbiased readouts of tract-specific changes that relate to impairment.

Neurodegeneration in the Spinal Ventral Horn Prior to Motor Impairment in Cervical Spondylotic Myelopathy

“…Tract-specific white matter changes in the posterior column and corticospinal tracts were already reported for this study cohort. 7 Age was statistically not different between patients and controls (Mann-Whitney U test: p=0.1075). Following inclusion criteria for study enrolment were fulfilled from all participants: age between 18-70 years, no MRI contradictions, no other neurological or mental conditions, and no pregnancy.…”

“…26 Jim 7.0 (Xynapse Systems, UK) was used to manually segment the cross-sectional spinal cord grey matter 7 This article has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction. The final published version may differ from this proof.…”

“…31 Additionally, manual slice-by-slice registration refined the registration accuracy. 7 Diffusion indices maps were smoothed with a 0.5x0.5x5mm 3 full-width at half maximum Gaussian kernel.…”

“…changes in diffusivity indices) using high-resolution structural and diffusion MRI protocols above stenosis in the cervical spinal cord in patients with CSM. 7 This allows us to address key questions of whether both the ventral and dorsal horns show signs of neurodegeneration prior to onset of marked This article has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction. The final published version may differ from this proof.…”

“…3 Next to focal myelopathy, [4][5][6] a cascade of neurodegenerative processes is evident in the grey and white matter above the site of compression in the cervical cord [7][8][9][10] and even in the sensorimotor cortex 11,12 that can be assessed non-invasively, amongst others, by magnetic resonance spectroscopy and diffusion tensor imaging (DTI) and other advanced MRI techniques sensitive to atrophy and microstructural changes. 13 Microstructural changes can be identified by diffusivity indices (e.g.…”