Analysis of the diffusion weighted MR microscopy data of excised spinal cord of a rat on the basis of the model of restricted diffusion

• Published in: Solid state nuclear magnetic resonance Vol. 25; no. 1; pp. 88 - 93
• Main Authors: Węglarz, W.P, Adamek, D, Markiewicz, J, Skórka, T, Kulinowski, P, Jasiński, A
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 2004
• Subjects: Animals; anisotropic diffusion; axon diameter distribution; Axons - chemistry; Axons - ultrastructure; Diffusion; Diffusion Magnetic Resonance Imaging - methods; gray matter; In Vitro Techniques; Male; Microscopy - methods; Microscopy, Electron; Models, Chemical; MR microscopy; nervous tissue; nonexponential diffusion; rat spinal cord; Rats; Rats, Wistar; restricted diffusion; Spinal Cord - chemistry; Spinal Cord - cytology; Thoracic Vertebrae - chemistry; Thoracic Vertebrae - cytology; Water - chemistry; white matter; white matter; nervous tissue; restricted diffusion; axon diameter distribution; gray matter; anisotropic diffusion; rat spinal cord; MR microscopy; nonexponential diffusion
• ISSN: 0926-2040; 1527-3326
• DOI: 10.1016/j.ssnmr.2003.03.006

Anisotropic diffusion in the excised rat spinal cord saturated with 0.9% saline was investigated using MR microimaging with b-values up to 8000 s/mm 2 for different diffusion times. Non-exponential transversal diffusion decay found in white matter (WM) and gray matter (GM) was fitted with 2 components (the “fast” and the “slow”). Significantly smaller non-exponential dependence was found for the longitudinal diffusion in the WM. Obtained results corresponding to restricted diffusion in the range from ∼2 to ∼7 μm were correlated with axon diameter distribution in the WM obtained from transmission electron micrographs. It was concluded that observed diffusion anisotropy in the spinal cord might be entirely explained by presence of the slow transversal component, arising from the restricted diffusion. The strict analytical description of the diffusion decay in nervous tissue requires taking into account continuous distribution of the space-scale of the restricting barriers. The simplified two-component analysis may be applicable for visualization of the nervous tissue in clinical practice.