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Diffusion tensor imaging (DTI) is a magnetic resonance imaging technique that enables the measurement of the restricted diffusion of water in tissue in order to produce neural tract images instead of using this data solely for the purpose of assigning contrast or colors to pixels in a cross-sectional image.
For example, Slicer's DTI package allows the conversion and analysis of DTI images. The results of such analysis can be integrated with the results from analysis of morphologic MRI, MR angiograms and fMRI. Other uses of Slicer include paleontology [14] and neurosurgery planning. [15] There is an active community at Slicer's Discourse server. [16]
One group of researchers (Iturria-Medina et al., 2008) [35] has constructed connectome data sets using diffusion tensor imaging (DTI) [36] [37] followed by the derivation of average connection probabilities between 70 and 90 cortical and basal brain gray matter areas. All networks were found to have small-world attributes and "broad-scale ...
The electromagnetic tensor is the combination of the electric and magnetic fields into a covariant antisymmetric tensor whose entries are B-field quantities. [1] = (/ / / / / /) and the result of raising its indices is = = (/ / / / / /), where E is the electric field, B the magnetic field, and c the speed of light.
Using diffusion tensor MRI, one can measure the apparent diffusion coefficient at each voxel in the image, and after multilinear regression across multiple images, the whole diffusion tensor can be reconstructed. [1] Suppose there is a fiber tract of interest in the sample.
Multiple methods are being used to study the potential brain abnormalities of individuals with PKD compared with “normal” individuals. These methods include SPECT studies, fMRI studies, and diffusion tensor imaging. The main problem with many of the studies concerned with the pathophysiology of the disorder is the small sample size.
T2 is a measure of the loss of coherence that excludes static dephasing, using an RF pulse to reverse the slowest types of dipolar interaction. There is in fact a continuum of interaction time-scales in a given biological sample, and the properties of the refocusing RF pulse can be tuned to refocus more than just static dephasing.
For example, for a macroscopic scalar field φ(x, t) and a macroscopic vector field A(x, t) the definition becomes: +, +. In the scalar case ∇ φ is simply the gradient of a scalar, while ∇ A is the covariant derivative of the macroscopic vector (which can also be thought of as the Jacobian matrix of A as a function of x ).