Direct and specific assessment of axonal injury and spinal cord microenvironments using diffusion correlation imaging
| Autor: | Peter J. Basser, Guofeng Zhang, Courtney J. Comrie, Dan Benjamini, Carlo Pierpaoli, Susan C. Schwerin, Elizabeth B. Hutchinson, Michal E. Komlosh |
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| Rok vydání: | 2020 |
| Předmět: |
Male
Electron Microscope Tomography Wallerian degeneration Materials science Anisotropic diffusion Cognitive Neuroscience Pyramidal Tracts specificity Neuroimaging Sensitivity and Specificity 050105 experimental psychology Article lcsh:RC321-571 axonal injury spectrum 030218 nuclear medicine & medical imaging Correlation 03 medical and health sciences 0302 clinical medicine Nuclear magnetic resonance Head Injuries Closed distribution medicine Animals 0501 psychology and cognitive sciences Diffusion (business) Anisotropy lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry DDCOSY 05 social sciences diffusion Ferrets Cervical Cord medicine.disease Spinal cord Immunohistochemistry Axons Diffusion Magnetic Resonance Imaging medicine.anatomical_structure Neurology nervous system correlation Closed head injury MADCO 030217 neurology & neurosurgery MRI Diffusion MRI |
| Zdroj: | NeuroImage NeuroImage, Vol 221, Iss, Pp 117195-(2020) |
| Popis: | We describe a practical two-dimensional (2D) diffusion MRI framework to deliver specificity and improve sensitivity to axonal injury in the spinal cord. This approach provides intravoxel distributions of correlations of water mobilities in orthogonal directions, revealing sub-voxel diffusion components. Here we use it to investigate water diffusivities along axial and radial orientations within spinal cord specimens with confirmed, tract-specific axonal injury. First, we show using transmission electron microscopy (TEM) and immunohistochemistry that tract-specific axonal beading occurs following Wallerian degeneration in the cortico-spinal tract (CST) as direct sequelae to closed head injury (CHI). We demonstrate that although some voxel-averaged diffusion tensor imaging (DTI) metrics are sensitive to this axonal injury, they are non-specific, i.e., they do not reveal an underlying biophysical mechanism of injury. Then we employed 2D diffusion correlation imaging (DCI) to improve discrimination of different water microenvironments by measuring and mapping the joint water mobility distributions perpendicular and parallel to the spinal cord axis. We determined six distinct diffusion spectral components that differ according to their microscopic anisotropy and mobility. We further identified a distinct microenvironment that is specifically associated with the injury-induced axonal degeneration, with reduced and increased diffusivities parallel and perpendicular, respectively, hallmarks of axonal beading. An injury-specific MR image of the CHI spinal cord was then generated, and a radiological-pathological correlation with histological silver staining % area was performed. The resulting large and significant correlation ( r = 0.79, p < 0.0001) indicates the high specificity with which DCI detects injury-induced tissue alterations. We predict that the ability to selectively image microstructural changes following axonal injury in the spinal cord can be useful in clinical and research applications, by enabling specific detection and increased sensitivity to injury-induced microstructural alterations. These results also encourage us to translate DCI to higher spatial dimensions to enable assessment of traumatic axonal injury, and possibly other diseases and disorders in the brain. |
| Databáze: | OpenAIRE |
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