Demyelination and degeneration in the injured human spinal cord detected with diffusion and magnetization transfer MRI

• Published in: NeuroImage (Orlando, Fla.) Vol. 55; no. 3; pp. 1024 - 1033
• Main Authors: Cohen-Adad, J., El Mendili, M-M., Lehéricy, S., Pradat, P-F., Blancho, S., Rossignol, S., Benali, H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2011; Elsevier Limited
• Subjects: Adult; Age; Aged; ASIA; Atrophy; Demyelinating Diseases - pathology; Diffusion; Diffusion Magnetic Resonance Imaging - methods; Diffusion-weighted MRI; Disability Evaluation; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging - methods; Magnetization transfer; Male; Middle Aged; Neurodegenerative Diseases - pathology; NMR; Nuclear magnetic resonance; Pathology; Spinal cord; Spinal Cord - pathology; Spinal Cord Injuries - pathology; Spinal cord injury; Young Adult; Magnetization transfer; GFA; MT; HARDI; FOV; Spinal cord injury; Atrophy; DW; ASIA; Diffusion-weighted MRI; MD; SCI; DTI; QBI; FA
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2010.11.089

Characterizing demyelination/degeneration of spinal pathways in traumatic spinal cord injured (SCI) patients is crucial for assessing the prognosis of functional rehabilitation. Novel techniques based on diffusion-weighted (DW) magnetic resonance imaging (MRI) and magnetization transfer (MT) imaging provide sensitive and specific markers of white matter pathology. In this paper we combined for the first time high angular resolution diffusion-weighted imaging (HARDI), MT imaging and atrophy measurements to evaluate the cervical spinal cord of fourteen SCI patients and age-matched controls. We used high in-plane resolution to delineate dorsal and ventrolateral pathways. Significant differences were detected between patients and controls in the normal-appearing white matter for fractional anisotropy (FA, p<0.0001), axial diffusivity (p<0.05), radial diffusivity (p<0.05), generalized fractional anisotropy (GFA, p<0.0001), magnetization transfer ratio (MTR, p<0.0001) and cord area (p<0.05). No significant difference was detected in mean diffusivity (p=0.41), T1-weighted (p=0.76) and T2-weighted (p=0.09) signals. MRI metrics were remarkably well correlated with clinical disability (Pearson's correlations, FA: p<0.01, GFA: p<0.01, radial diffusivity: p=0.01, MTR: p=0.04 and atrophy: p<0.01). Stepwise linear regressions showed that measures of MTR in the dorsal spinal cord predicted the sensory disability whereas measures of MTR in the ventro-lateral spinal cord predicted the motor disability (ASIA score). However, diffusion metrics were not specific to the sensorimotor scores. Due to the specificity of axial and radial diffusivity and MT measurements, results suggest the detection of demyelination and degeneration in SCI patients. Combining HARDI with MT imaging is a promising approach to gain specificity in characterizing spinal cord pathways in traumatic injury. ► We combined DTI, magnetization transfer and atrophy measure in spinal cord injury. ► Differences in normal-appearing white matter for DTI and MTR. ► Results suggest degeneration and demyelination in SCI patients. ► DTI, MTR and atrophy can predict impairment in spinal cord injury (SCI).