Diffusion tensor imaging and fiber tractography
Updates to Article Attributes
Title
was changed:
Diffusion tensor-tensor MRI imaging (DTI) and fiber tracking (FT)tractography
Body
was changed:
Diffusion-tensor imaging (DTI) and fiberis a MRI technique that uses anisotropic diffusion to estimate the axonal (white matter) organisation of the brain. Fiber tractography (FT) are new methods that can demonstrate the orientation and integrity of white matter fibers in vivois a 3D reconstruction technique to access neural tracts using data collected by DTI.
Within cerebral white matter, water molecules tend to diffuse more freely along the direction of axonal fascicles than across them. Such directional dependence of diffusivity is termed anisotropy.
Combining anisotropic data with the directionality will led to fiber tractography (FT) in which 3D pathways of white matter tracts are reconstructed form continuous trajectories.
Colour coding
- red for fibres crossing from left to right
- green for fibres traversing in antero-posterior direction
- blue for fibres going from superior to inferior
Quantitative analysis methods
- ROI(region of interest)
bassedbased - voxel based
- histogram analysis
- tractography/fibre tracking
Physics of DTI
- DTI provides quantitative analysis of the magnitude and directionality of water molecules
. - the word tensor indicates a 3 x 3 matrix used here with eigen values and eigen vectors as its constituents
. - the two main parameters derived from DTI data are mean diffusivity (MD) or in other term
Apparentapparent diffusion coefficient (ADC) and fractional anisotropy (FA). - FA reflects the directionality of molecular displacement by diffusion and vary between 0 (isotropic diffusion) and 1 (infinite anisotropicdiffusion)
.FA. FA value of CSF is 0 - MD reflects the average magnitude of molecular displacement by diffusion
, The. The more the MD value, the more the isotropic is the medium. - AD - axial diffusivity represents the longest eigen vector
- RD - radial diffusivity represents the average of two shorter eigen vectors
. - DTI data aquisition is done by SE-EPI with application of diffusion gradients in multiple directions
-<p><strong>Diffusion-tensor imaging (DTI) and fiber tractography (FT)</strong> are new methods that can demonstrate the orientation and integrity of white matter fibers in vivo.</p><p>Within cerebral white matter, water molecules tend to diffuse more freely along the direction of axonal fascicles than across them. Such directional dependence of diffusivity is termed <strong><em>anisotropy</em></strong>.</p><p>Combining anisotropic data with the directionality will led to fiber tractography (FT) in which 3D pathways of white matter tracts are reconstructed form continuous trajectories.</p><h4>Colour coding </h4><ul>-<li>red for fibres crossing from left to right</li>-<li>green for fibres traversing in antero-posterior direction</li>-<li>blue for fibres going from superior to inferior</li>-</ul><h4>Quantitative analysis methods</h4><ul>-<li>ROI(region of interest) bassed</li>-<li>voxel based</li>-<li>histogram analysis</li>-<li>tractography/fibre tracking </li>-</ul><h4>Physics of DTI</h4><ul>-<li>DTI provides quantitative analysis of the magnitude and directionality of water molecules.</li>-<li>the word tensor indicates a 3 x 3 matrix used here with eigen values and eigen vectors as its constituents .</li>-<li>the two main parameters derived from DTI data are mean diffusivity (MD) or in other term Apparent diffusion coefficient (ADC) and fractional anisotropy (FA).</li>-<li>FA reflects the directionality of molecular displacement by diffusion and vary between 0 (isotropic diffusion) and 1 (infinite anisotropicdiffusion).FA value of CSF is 0</li>-<li>MD reflects the average magnitude of molecular displacement by diffusion, The more the MD value, the more the isotropic is the medium.</li>-<li>AD - axial diffusivity represents the longest eigen vector </li>-<li>RD - radial diffusivity represents the average of two shorter eigen vectors.</li>-<li>DTI data aquisition is done by SE-EPI with application of diffusion gradients in multiple directions</li>- +<p><strong>Diffusion-tensor imaging (DTI) </strong>is a MRI technique that uses anisotropic diffusion to estimate the axonal (white matter) organisation of the brain. <strong>Fiber tractography (FT)</strong> is a 3D reconstruction technique to access neural tracts using data collected by DTI.</p><p>Within cerebral white matter, water molecules tend to diffuse more freely along the direction of axonal fascicles than across them. Such directional dependence of diffusivity is termed anisotropy.</p><h4>Colour coding </h4><ul>
- +<li>red for fibres crossing from left to right</li>
- +<li>green for fibres traversing in antero-posterior direction</li>
- +<li>blue for fibres going from superior to inferior</li>
- +</ul><h4>Quantitative analysis methods</h4><ul>
- +<li>ROI (region of interest) based</li>
- +<li>voxel based</li>
- +<li>histogram analysis</li>
- +<li>tractography/fibre tracking </li>
- +</ul><h4>Physics of DTI</h4><ul>
- +<li>DTI provides quantitative analysis of the magnitude and directionality of water molecules</li>
- +<li>the word tensor indicates a 3 x 3 matrix used here with eigen values and eigen vectors as its constituents</li>
- +<li>the two main parameters derived from DTI data are mean diffusivity (MD) or in other term apparent diffusion coefficient (ADC) and fractional anisotropy (FA)</li>
- +<li>FA reflects the directionality of molecular displacement by diffusion and vary between 0 (isotropic diffusion) and 1 (infinite anisotropicdiffusion). FA value of CSF is 0</li>
- +<li>MD reflects the average magnitude of molecular displacement by diffusion. The more the MD value, the more the isotropic is the medium</li>
- +<li>AD - axial diffusivity represents the longest eigen vector </li>
- +<li>RD - radial diffusivity represents the average of two shorter eigen vectors</li>
- +<li>DTI data aquisition is done by SE-EPI with application of diffusion gradients in multiple directions</li>
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Title
was changed:
Diffusion-tensor imaging and fiber tractography
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