Journal ArticleDOI
A Simplified Method to Measure the Diffusion Tensor from Seven MR Images
Peter J. Basser,Carlo Pierpaoli +1 more
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TLDR
Although diffusion tensor MRI with seven DWIs may be useful for clinical applications where rapid scanning and data processing are required, it does not provide estimates of the uncertainty of the measured imaging parameters, rendering it susceptible to noise and systematic artifacts.Abstract:
Analytical expressions of the diffusion tensor of water, D, and of scalar invariants derived from it, are given in terms of the intensities of seven diffusion-weighted images (DWIs). These formulas simplify the post-processing steps required in diffusion tensor imaging, including estimating D in each voxel (from the set of b-matrices and their corresponding DWIs), and then computing its eigenvalues, eigenvectors, and scalar invariants. In a study conducted using artifact-free DWIs with high diffusion weighting (bmax approximately 900 s/mm2, maps of Trace(D) and the Relative and Lattice Anisotropy indices calculated analytically and by multivariate linear regression showed excellent agreement in brain parenchyma of a healthy living cat. However, the quality of the analytically computed maps degraded markedly as diffusion weighting was reduced. Although diffusion tensor MRI with seven DWIs may be useful for clinical applications where rapid scanning and data processing are required, it does not provide estimates of the uncertainty of the measured imaging parameters, rendering it susceptible to noise and systematic artifacts. Therefore, care should be taken when using this technique in radiological applications.read more
Citations
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Journal ArticleDOI
Diffusion tensor imaging: Concepts and applications
D. Le Bihan,J.-F. Mangin,Cyril Poupon,Chris A. Clark,Sabina Pappatà,Nicolas Molko,Hugues Chabriat +6 more
TL;DR: The concepts behind diffusion tensor imaging are reviewed and potential applications, including fiber tracking in the brain, which, in combination with functional MRI, might open a window on the important issue of connectivity.
Journal ArticleDOI
Dysmyelination Revealed through MRI as Increased Radial (but Unchanged Axial) Diffusion of Water
Sheng-Kwei Song,Shu-Wei Sun,Shu-Wei Sun,Michael J. Ramsbottom,Chen Chang,John H. Russell,Anne H. Cross +6 more
TL;DR: The use of magnetic resonance diffusion tensor imaging to quantify the effect of dysmyelination on water directional diffusivities in brains of shiverer mice in vivo suggests that changes in lambda(perpendicular) and lambda(parallel) may potentially be used to differentiate myelin loss versus axonal injury.
Journal ArticleDOI
Diffusion Tensor Imaging of the Brain
TL;DR: Diffusion tensor imaging (DTI) is a promising method for characterizing microstructural changes or differences with neuropathology and treatment and the biological mechanisms, acquisition, and analysis of DTI measurements are addressed.
Journal ArticleDOI
Diffusion tensor imaging detects and differentiates axon and myelin degeneration in mouse optic nerve after retinal ischemia.
TL;DR: The hypothesis that lambdaparallel and lambdaperpendicular hold promise as specific markers of axonal and myelin injury, respectively, and, further, that the coexistence of axon andMyelin degeneration does not confound this utility, are supported.
Journal ArticleDOI
Demyelination increases radial diffusivity in corpus callosum of mouse brain.
Sheng-Kwei Song,Jun E. Yoshino,Jun E. Yoshino,Tuan Q. Le,Shiow Jiuan Lin,Shu-Wei Sun,Anne H. Cross,Regina C. Armstrong,Regina C. Armstrong +8 more
TL;DR: In this article, the authors used diffusion tensor imaging (DTI) derived parameters to assess the extent of axonal damage, demyelination and axonal degeneration.
References
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Microstructural and physiological features of tissues elucidated by quantitative-diffusion-tensor MRI
Peter J. Basser,Carlo Pierpaoli +1 more
TL;DR: Quantitative-diffusion-tensor MRI consists of deriving and displaying parameters that resemble histological or physiological stains, i.e., that characterize intrinsic features of tissue microstructure and microdynamics that are objective, and insensitive to the choice of laboratory coordinate system.
Journal ArticleDOI
Estimation of the Effective Self-Diffusion Tensor from the NMR Spin Echo
TL;DR: The diagonal and off-diagonal elements of the effective self-diffusion tensor, Deff, are related to the echo intensity in an NMR spin-echo experiment.
Journal ArticleDOI
Toward a quantitative assessment of diffusion anisotropy
Carlo Pierpaoli,Peter J. Basser +1 more
TL;DR: New indices calculated from the entire diffusion tensor are rotationally invariant (RI) and show that anisotropy is highly variable in different white matter regions depending on the degree of coherence of fiber tract directions.
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