Spinal Cord Injury & Repair

Imaging

Electron Microscopy

Electron microscopy (EM) is a valuable tool that can be used to detect the ultrastructure of myelin sheaths within injured and healthy rat spinal cords. A loss of the dense lines and a separation of myelin from axolemma can be seen in. Similarly, after contusive spinal cord injury, there will be spared axons around the site of injury that are anatomically continued but electrically defunct due to demyelination. EM has also been used by our group to study the remyelination capability of our oligodendrocyte precursor cells.

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EM of healthy myelin surrounding axons.
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EM of an injured spinal cord with degrading myelin.
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EM showing remyelination after OP transplants.
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Magnetic Resonance Imaging

Using magnetic resonance imaging (MRI), we can visualize pathological features of SCI and monitor its progression. Our approach is based on fusing T2 and DTI images to explore pathological change due to the injury. The figure below compares in vivo T2-weighted (T2), fractional ansiotropy (FA), axial diffusivity (AD), and color map (CM) images of an injured spinal cord that were acquired from three locations in the vicinity of the injury: the epicenter to injury, rostral (toward the head) to injury, and caudal (toward the tail) to injury. The yellow arrows indicate significant damage to the white matter, and the red arrows indicate signficant damage to the grey matter.

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MRI images of an injured spinal cord taken in vivo.
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Diffusion Tensor Imaging

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Ex vivo DTI fiber reconstruction of an injured spinal cord.

Diffusion tensor imaging (DTI) is a magnetic resonance technique that uses diffusion anisotropy to generate contrast. It can provide anisotropy maps and orientation maps, or a combination of the two. DTI provides superior contrast for outlining the axonal organization in the central nervous system (CNS).

Ex vivo DTI fiber tracking of an injured spinal cord. The grey areas indicates white matter, the green areas indicate gray matter, and the red areas indicate injury-induced vacuoles. The overlying yellow curves represent survival fibers that were reconstructed by FACT. Fibers are overlaid.