Water diffusion anisotropy. Medical search. Frequent questions

Microscopic fractional anisotropy (µFA) is a diffusion-weighted magnetic resonance imaging (dMRI) metric that is sensitive to neuron microstructural features without being confounded by the orientation dispersion of axons and dendrites. (uwo.ca)
Microscopic fractional anisotropy (µFA) is a dMRI metric that quantifies the asymmetry of water diffusivity across different directions. (uwo.ca)
Inverse correlation was found between fractional anisotropy in the motor thalamus one day following ablation and tremor improvement in both patient groups, with lower values before treatment associated with better outcome (tremor relief) in essential tremor patients. (biorxiv.org)
Fractional anisotropy (FA), a common DTI measurement of water diffusion properties, was used as a marker of WM microstructure integrity. (cdc.gov)
Finally, changes in left dlPFC - IPC rs-FC correlated with the change in left SLF structural connectivity as measured by fractional anisotropy (FA) in the Tenacity group only. (nature.com)
Josh has research experience conducting fractional anisotropy and free-water analyses with diffusion-weighted MRI, and is working on connectome analysis to derive functional network targets for non-invasive treatment of neuropsychiatric disorders. (brandeis.edu)
By fitting a tensor model to quantify the directionality of water diffusion a Diffusion Tensor Image (DTI) can be derived and scalar measures, such as fractional anisotropy (FA), can then be estimated from the DTI to summarise quantitative microstructural information for clinical studies. (frontiersin.org)
In clinical settings and neuroscience research, fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) are the most commonly used scalar measures. (frontiersin.org)
Fractional anisotropy, or FA, quantifies the anisotropy of water diffusion. (harvard.edu)
In a 3 x 3 configuration, a diffusion tensor matrix yields several specific assessments, including the mean diffusivity (MD) or the apparent diffusion coefficient (ADC), which computes the average degree of diffusion of water molecules over all spatial directions, as well as mathematical vectors and values that describe anisotropy, such as fractional anistrophy (FA). (diagnosticimaging.com)
A high fractional anisotropy (FA) reflects intact axonal membranes, myelin sheaths, and a parallel arrangement of neurofibrils. (biomedcentral.com)
image: Reduction in fractional anisotropy (FA) in obese patients compared to the control group: At the intersection of the alignment vectors, a large cluster of FA decrease located in the corpus callosum on the left. (eurekalert.org)
From DTI, the researchers derived a measure called fractional anisotropy (FA), which correlates with the condition of the brain's white matter. (eurekalert.org)
Jones, 2008 ), this 2nd order tensor can be used to extract scalar measures, such as the mean diffusivity (MD) and the diffusion fractional anisotropy (FA) ( Basser and Pierpaoli, 1996 ). (frontiersin.org)
Fractional anisotropy, a metric derived from DTI, revealed significant brain abnormalities in blast-exposed animals. (marquette.edu)
This classifier was tested on a real-world dataset using the gradient-based hierarchical hybrid Multi-scale Fractional Anisotropy Tensor (MFAT) filter to segment the cracks. (usc.edu)
This imaging technique allows researchers to measure the uniformity of water movement (fractional anisotropy) throughout the brain. (neuronewsinternational.com)
Abnormally low fractional anisotropy in white matter indicates axon damage and has previously been associated with cognitive impairment in patients with traumatic brain injury (the researchers also use DTI in an ongoing study of amateur football players to assess possible brain injury from repeatedly heading footballs). (neuronewsinternational.com)
One of the measures most commonly derived from diffusion data is fractional anisotropy (FA), which quantifies how strongly directional the local tract structure is. (ox.ac.uk)

This polarized emission gradually returns to unpolarized fluorescence depending on rotational diffusion and other factors. (horiba.com)
different rotational diffusion coefficients and to determine the Address reprint requests to Dr. Karim Snoussi, E-mail: karim.snoussi@ populations of coexisting oligomers. (lu.se)
B 124, 154-164 (1997) +} {+ reference: Tjandra N, Garrett DS, Gronenborn AM, Bax A, Clore GM, Defining long range order in NMR structure determination from the dependence of heteronuclear relaxation times on rotational diffusion anisotropy. (lu.se)

The ability to spatially map the diffusion of free water protons in vivo using 1 H MR imaging and the observation that the diffusion of free water protons is reduced in acutely infarcted brain tissue are responsible for the widespread use of these techniques in clinical imaging [ 3 , 4 , 5 , 6 , 7 , 8 ]. (ajronline.org)
Here we addressed this issue by quantifying regional voxelwise changes in brain gray matter volume, white matter microstructure, extracellular free water (FW) distribution, and ventricular volume from pre- to post-flight in a sample of 30 astronauts. (nature.com)
Diffusion-weighted Imaging (DWI) is a non-invasive imaging technique based on Magnetic Resonance Imaging (MRI) principles to measure water diffusivity and reveal details of the underlying brain micro-structure. (frontiersin.org)
DWI is extensively used in clinical neuroscience research because it is particularly sensitive to the diffusivity of water molecules in brain tissues and it can help to reconstruct fibre bundles and estimate brain connectivity. (frontiersin.org)
The big discovery came when this technique was used in patients with neurological disorders because water diffuses faster in the direction of fibers in the brain,' said Dr. Denis Le Bihan, director of the laboratory of anatomy and functional neurology at Service Hospitalier Frederic Joliot in Orsay, France. (diagnosticimaging.com)
Diffusion-weighted magnetic resonance imaging (dMRI) measurements and models provide information about brain connectivity and are sensitive to the physical properties of tissue microstructure. (frontiersin.org)
Axial fluid-attenuated inversion recovery (FLAIR) image (top left), diffusion-weighted image (DWI) (top right), and axial and sagittal T1-weighted (T1W) images (bottom) in a 40-year-old man with a history of intravenous drug abuse and fever demonstrate multiple enhancing focal brain lesions in the gray-white matter junction (arrow) compatible with septic emboli. (medscape.com)
The diffusion ellipsoid defines the magnitude and direction of the diffusion of water molecules in each voxel in the brain. (medscape.com)
In the second tutorial we described how to normalize a set of diffusion tensor images (DTI) and run statistics on the normalized brain images (including voxel bases analyses). (diffusion-imaging.com)
PURPOSE: To characterize the maturational changes in water diffusion within central gray matter nuclei and central white matter pathways of the human brain by using diffusion-tensor magnetic resonance (MR) imaging. (wustl.edu)
CONCLUSION: Changes in magnitude and anisotropy of water diffusion follow stereotypical time courses during brain development that can be empirically described with multiexponential regression models, which suggests that quantitative scalar parameters derived from diffusion-tensor MR imaging may provide clinically useful developmental milestones for brain maturity. (wustl.edu)
Primary Blast Traumatic Brain Injury in the Rat: Relating Diffusion Te" by Matthew D. Budde, Alok Shah et al. (marquette.edu)
and Stemper, Brian D., "Primary Blast Traumatic Brain Injury in the Rat: Relating Diffusion Tensor Imaging and Behavior" (2013). (marquette.edu)
Diffusion tensor MR imaging of the human brain. (ox.ac.uk)
PURPOSE: To assess intrinsic properties of water diffusion in normal human brain by using quantitative parameters derived from the diffusion tensor, D, which are insensitive to patient orientation. (ox.ac.uk)
Noninvasive mapping of water diffusional exchange in the human brain using filter-exchange imaging. (lu.se)
Towards non-parametric diffusion-T1 characterization of crossing fibers in the human brain. (lu.se)
Computing and visualising intra-voxel orientation-specific relaxation-diffusion features in the human brain. (lu.se)
The researchers are using an advanced MRI-based imaging technique called diffusion tensor imaging (DTI) to identify injured brain areas. (neuronewsinternational.com)
Diffusion imaging also promises to further our understanding of brain disorders and abnormalities such as tumors, multiple sclerosis, and schizophrenia. (uni-freiburg.de)
A novel diffusion anisotropy metric is presented that provides anatomically interpretable measurements of tracts that are robust in crossing areas of the brain. (pitt.edu)
There has been much recent interest in using magnetic resonance diffusion imaging to provide information about anatomical connectivity in the brain, by measuring the anisotropic diffusion of water in white matter tracts. (ox.ac.uk)

Mean diffusivity (MD) quantifies the total amount of diffusion, which is mainly determined by the water content. (harvard.edu)
Diffusion MRI makes use of sequences developed to reveal differences in tissue characteristices with the parameters mean diffusivity D and the anisotropy FA. (uni-freiburg.de)

The aspect of DTI of most interest to neuroimaging is the diffusion coefficient, which reflects diffusion distance over time. (diagnosticimaging.com)
normal states and abnormal conditions are easily interpreted through the use of DWI in conjunction with the use of apparent diffusion coefficient (ADC) imaging by correlating findings of hyperintensity on DWI images with findings of hypointensity on ADC images (see the images below). (medscape.com)
On DWIs commonly used to diagnose acute stroke (see the image below), diffusion is described by using the apparent diffusion coefficient (ADC). (medscape.com)
Isotropic diffusion coefficient (D̄) and diffusion anisotropy (A σ ) were measured in the corpus callosum, internal capsule, caudate nucleus, lentiform nucleus, and thalamus. (wustl.edu)
Isotropic diffusion coefficient ({\=D}) and diffusion anisotropy (Aσ) were measured in the corpus callosum, internal capsule, caudate nucleus, lentiform nucleus, and thalamus. (wustl.edu)
Nuclear magnetic resonance measurement of ni muscle: anisotropy of the diffusion coefficient of the intracellular water. (forexrin.com)

DTI allows clinicians to look at anisotropic diffusion in white-matter tracts, but it is limited in its ability to demonstrate spatial and directional anisotropy. (medscape.com)
Furthermore, the textural noise suppression and refinement are carried out by using an anisotropic diffusion filter. (usc.edu)
Guidelines are provided to select the parameters for the anisotropic diffusion filter. (usc.edu)
Multidimensional encoding of restricted and anisotropic diffusion by double rotation of the q vector. (lu.se)

To address this question, we present a novel approach that combines direct tracer measurements of entire white matter trajectories in macaque monkeys with diffusion MRI tractography of both macaques and humans. (jneurosci.org)
The approach allows us to provide explicit validation of diffusion tractography and transfer tractography strategies across species to test the extent to which inferences from macaques can be applied to human neuroanatomy. (jneurosci.org)
We use a novel combination of accurate mapping of whole WM trajectories from chemical tracing, with diffusion MRI tractography. (jneurosci.org)
The anisotropy color-coding tractography of the CST was visually evaluated. (ajnr.org)
It uses diffusion tensor tractography as an anatomic landmark, and diffusion tensor metrics are calculated along the drawn tractographic image. (ajnr.org)
72 hours) were examined in each subject by diffusion tensor tractography (DTT). (dovepress.com)

Random motion of water molecules (diffusion) in the presence of a strong magnetic gradient results in MR signal loss as a result of the dephasing of spin coherence ( Fig. 1 ). (ajronline.org)
Diffusion magnetic resonance imaging (dMRI) is a specialized imaging technique that is sensitive to the motion of water molecules in tissue, which is affected by interactions with obstacles such as membranes and macromolecules. (uwo.ca)
Diffusion is a process describing the motion of water molecules in biological tissue. (uni-freiburg.de)

The application of a pair of strong gradients to elicit differences in the diffusivity of water molecules among various biologic tissues is known as diffusion sensitization or diffusion weighting [ 22 , 23 ]. (ajronline.org)
Diagram shows loss of intensity of MR signal (S, solid line ) resulting from inefficient rephasing of dephased spins because of displacement of water molecules (diffusion) between application of bipolar gradients ( G ). With decreased diffusion (reduced displacement of water molecules), rephasing process is more efficient and signal loss is predominantly caused by T2 decay ( dotted line ). (ajronline.org)
11 FA values are calculated from the axial and radial diffusivity of water molecules. (ajnr.org)
values) to precisely characterise the movement of water molecules in different directions as a measure of the resulting changes in signal intensity. (frontiersin.org)
It chronicles the diffusion of water molecules within themselves. (diagnosticimaging.com)
A sphere or ellipsoid, which is mathematically described as a tensor, simplifies the visualization of moving water molecules. (diagnosticimaging.com)
Diffusion, or brownian movement, denotes the random motion of molecules. (medscape.com)
To measure the presence of anisotropy in the white matter requires a tensor D , which describes the mobility of molecules in a particular direction and correlation between these directions. (medscape.com)
The eigenvector corresponding to the largest eigenvalue, termed the principal eigenvector, defines the main direction of diffusion of water molecules in that voxel (see the image below). (medscape.com)
An anisotropic liquid has the fluidity of a normal liquid, but has an average structural order relative to each other along the molecular axis, unlike water or chloroform, which contain no structural ordering of the molecules. (everipedia.org)

In the last 10-15 years, MR imaging techniques have been increasingly applied to the study of molecular displacement (diffusion) in biologic tissue [ 1 , 2 ]. (ajronline.org)
In this paper, we briefly describe the tensor theory used to characterize molecular diffusion in white matter and how the tensor elements are measured experimentally using diffusion-sensitive MR imaging. (ajronline.org)
Adding diffusion-sensitizing gradients to an imaging sequence (spatial encoding) constitutes the basis for diffusion-weighted MR imaging. (ajronline.org)
µFA may potentially act as a surrogate biomarker for neurodegeneration, demyelination, and other pathological changes to neuron microstructure with greater specificity than other dMRI techniques that are sensitive to orientation dispersion, such as diffusion tensor imaging. (uwo.ca)
All patients underwent MRI including T1, T2-FLAIR and diffusion weighted imaging before treatment and at one day, 7-10 days, 1-3 months, and 6 months or more following it. (biorxiv.org)
In this preliminary study, we used diffusion tensor imaging (DTI) to investigate the effectiveness of respirator use in protecting workers' white matter (WM) from the harmful effects related to welding fume exposure. (cdc.gov)
A combined analysis of resting state functional connectivity (rs-FC) and diffusion tensor imaging (DTI) yielded convergent results - change in communication within the left fronto-parietal network after two weeks of playing Tenacity compared to a control game. (nature.com)
The MDD group ( n = 29) and a healthy control group ( n = 47) underwent diffusion tensor imaging (DTI) scans and an analysis was conducted using TBSS. (cambridge.org)
However, time constraints in clinical practice lead to low angular resolution diffusion imaging (LARDI) acquisitions that can cause inaccurate FA value estimates when compared to those generated from high angular resolution diffusion imaging (HARDI) acquisitions. (frontiersin.org)
On the other hand, Diffusion Weighted Imaging (DWI) can measure the water diffusivity within tissues and reveal their microstructure and integrity ( 1 ). (frontiersin.org)
Each set of images at different gradient directions can be summarised using a Diffusion Tensor Imaging (DTI) model to uncover microstructural information by describing water's directionality and its corresponding quantitative anisotropy ( 2 ). (frontiersin.org)
Diffusion tensor imaging (DTI) is capable of resolving individual pathways in the brainstem and individual nuclei in the thalamus (not surgically relevant). (harvard.edu)
For example, the corticospinal and corticobulbar tracts (motor), arcuate fasciculus (language), optic radiations (visual) can be modeled by diffusion tensor imaging. (harvard.edu)
Diffusion tensor imaging is a relative newcomer in MR imaging. (diagnosticimaging.com)
In an overview of the principles underlying diffusion tensor imaging, Dr. Olaf Dietrich from Ludwig-Maximilian University in Munich explained that diffusion is microscopic stochastic motion induced by thermal energy. (diagnosticimaging.com)
Diffusion tensor imaging (DTI) is used to examine the neural connectivity and integrity of the white matter. (biomedcentral.com)
Developments in MRI like diffusion tensor imaging (DTI), a technique that tracks the diffusion of water along the brain's signal-carrying white matter tracts, have enabled researchers to study this damage directly. (eurekalert.org)
Diffusional Kurtosis Imaging (DKI) quantifies the degree of non-Gaussian diffusion in biological tissue from dMRI. (frontiersin.org)
Diffusion-weighted imaging (DWI) is a well-established magnetic resonance imaging (MRI) method for diagnosing cerebral ischemia. (medscape.com)
Imaging and interpretation of water diffusion have improved with the development of diffusion tensor imaging (DTI). (medscape.com)
Summary/conclusions Modalities of measuring physiological change after SRC were categorised into the following: functional MRI, diffusion tensor imaging, magnetic resonance spectroscopy, cerebral blood flow, electrophysiology, heart rate, exercise, fluid biomarkers and transcranial magnetic stimulation. (bmj.com)
All studies included diffusion tensor-encoded echo-planar MR imaging. (wustl.edu)
Cardiovascular magnetic resonance (CMR) can through the two methods 3D FLASH and diffusion tensor imaging (DTI) give complementary information on the local orientations of cardiomyocytes and their laminar arrays. (biomedcentral.com)
Eight explanted rat hearts were perfused with Gd-DTPA contrast agent and fixative and imaged in a 9.4T magnet by two types of acquisition: 3D fast low angle shot (FLASH) imaging, voxels 50 × 50 × 50 μm, and 3D spin echo DTI with monopolar diffusion gradients of 3.6 ms duration at 11.5 ms separation, voxels 200 × 200 × 200 μm. (biomedcentral.com)
Diffusion weighted imaging with IVIM and DTI fitting to obtain muscle microstructure and muscle architecture, for information look here» . (muscle-atlas.org)
Diffusion tensor imaging (DTI), a promising method to detect blast injury in humans, was performed on fixed brains to detect and visualize the spatial dependence of blast injury. (marquette.edu)
Diffusion MR imaging has demonstrated its value for the early detection of stroke. (uni-freiburg.de)
Diffusion magnetic resonance imaging (dMRI) is an advanced MRI methodology that can be used to probe the microstructure of biological tissue. (pitt.edu)
This thesis presents contributions in three areas of diffusion imaging technology: diffusion reconstruction, quantification, and validation of derived metrics. (pitt.edu)
This work represents a new accurate quantification of axonal water content through diffusion imaging. (pitt.edu)
Filip focused his PhD on developing advanced diffusion MRI methods in close collaboration with Random Walk Imaging. (rwi.se)
TBSS aims to improve the sensitivity, objectivity and interpretability of analysis of multi-subject diffusion imaging studies. (ox.ac.uk)
We describe TBSS in detail and present example TBSS results from several diffusion imaging studies. (ox.ac.uk)

Advanced mathematical algorithms can be applied to reveal the connectivity of white matter fibres from multi-directional diffusion tensor measurements. (uni-freiburg.de)
The metric, directional Axonal Volume (dAV) provides an estimate of directional water content of the tract based on the (ODF) and proton density map. (pitt.edu)

DTI uses diffusion vectors to measure the directionality of white matter tracts. (harvard.edu)
Since the diffusion of water is limited by the presence of myelin and axonal membranes, the directionality of white matter tracts can be inferred from studies of water diffusion patterns. (harvard.edu)
DTI is a useful tool for examining and quantifying white matter microstructure, including the orientation and integrity of white matter tracts, by detecting the diffusion of water in neural tissue in vivo [ 10 ]. (biomedcentral.com)
In the corpus callosum and pyramidal tracts, the ratio of parallel to perpendicular diffusivities was approximately threefold higher than previously reported, and diffusion appeared cylindrically symmetric. (ox.ac.uk)

Acquiring diffusion-weighted images with at least two different b values (commonly 20 and 1000 sec/mm 2 ) while keeping the TE fixed allows the determination of the ADC value for each image voxel ( Fig. 3 ). (ajronline.org)

CONCLUSION: A quantitative characterization of water diffusion in anisotropic, heterogeneously oriented tissues is clinically feasible. (ox.ac.uk)
To support both the groundwater and water-distribution system efforts, ATSDR should conduct in depth searching of records for additional quantitative data and detailed information of interconnections between the water-distribution systems. (cdc.gov)

12 Axial diffusivity is defined by the axial eigenvalue ( λ 1 value), ie, the mean magnitude of water diffusion parallel to the axon. (ajnr.org)
Radial diffusivity is defined by the radial eigenvalue (average value of λ 2 and λ 3), ie, the mean magnitude of water diffusion perpendicular to the axon. (ajnr.org)

Even though the thickness of the myelin sheath is in the order of micrometres, well beyond the MRI spatial resolution, its presence influences several physical properties that can be probed with MRI, from longitudinal and transversal relaxation phenomena to water molecule diffusion processes. (biorxiv.org)
Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data. (ox.ac.uk)

Diffusion tensor metrics of the segmented CST, including FA values, axial eigenvalues, and radial eigenvalues, were evaluated by using tract-specific analysis. (ajnr.org)
Axial diffusion-weighted image (DWI) (top left), T2-weighted (T2W) image (top right), fluid-attenuated inversion recovery (FLAIR) image (bottom left), and contrast-enhanced T1W (bottom right) image demonstrate a right convexity meningioma, which appears hypointense on DWI image. (medscape.com)

Massively multidimensional diffusion-relaxation correlation MRI. (lu.se)

In Chapter 3 , a modified signal representation was investigated to estimate µFA and other indices while mitigating contaminating partial volume effects from free water, such as the cerebrospinal fluid in ventricles. (uwo.ca)
MATERIALS AND METHODS: Maps of the principal diffusivities of D, of Trace(D), and of diffusion anisotropy indices were calculated in eight healthy adults from 31 multisection, interleaved echo-planar diffusion-weighted images acquired in about 25 minutes. (ox.ac.uk)

dMRI takes advantage of the relationship between water diffusion and tissue properties to reveal details about tissue architecture on a microscopic level. (uwo.ca)
In this work, we implemented DKI in the Diffusion in Python (DIPY) project-a large collaborative open-source project which aims to provide well-tested, well-documented and comprehensive implementation of different dMRI techniques. (frontiersin.org)
This is because the image contrast provided by dMRI is sensitive to micron-scale distances that are probed through the random motion of water within a small amount of time between the two gradient pulses ( Kiselev, 2021 ). (frontiersin.org)
dMRI can provide orientation information by modeling the process of water diffusion in white matter. (pitt.edu)

In particular, FA has been shown to be a useful research metric to identify tissue abnormalities in neurological disease (e.g. decreased anisotropy as a proxy for tissue damage). (frontiersin.org)
dAV is a directionally sensitive metric and can separate anisotropic water content for each fiber population, providing a quantification in milliliters of water. (pitt.edu)
dAV shows promise as a new anatomically interpretable metric of axonal connectivity that is not confounded by factors such as axon dispersion, crossing and local isotropic water content. (pitt.edu)

Anisotropy measurements reveal the average angular displacement of the fluorophore that occurs between absorption and subsequent emission of a photon. (everipedia.org)
This can, in turn, drastically shorten the time needed for diffusion encoding, increase the signal-to-noise ratio, and facilitate measurements at shorter diffusion times. (edu.au)

Physicists use the term anisotropy to describe direction-dependent properties of materials. (everipedia.org)

Moreover, we illustrate how DKI provides more general characterization of non-Gaussian diffusion compatible with complex white matter fiber architectures and gray matter, and we include a novel mean kurtosis index that is invariant to the confounding effects due to tissue dispersion. (frontiersin.org)

Maps of parameters derived from D were also used to segment tissues based on their diffusion properties. (ox.ac.uk)

Diffusion MRI is a powerful tool to characterize tissue micro structure and to identify and differentiate disease processes. (uni-freiburg.de)

Thus, the b value (diffusion sensitization) can be increased by using stronger ( G ) and longer (δ) pulsed gradients or by lengthening the time between the pulsed gradients (Δ). (ajronline.org)
Degree of diffusion sensitization (b value) is determined by duration (δ) and strength (height) of sensitizing pulsed-gradients ( G ), and time interval between two pulsed gradients (Δ). (ajronline.org)

Abstract: Civil, mechanical, and aerospace infrastructures are subjected to applied loads and environmental forces like earthquakes, wind, and water waves in their operating lifespan. (usc.edu)

The first application of the technique was in stroke - hours after the acute episode, a diffusion-perfusion mismatch could identify an ischemic penumbra, which could be addressed by treatment. (diagnosticimaging.com)

This scheme is commonly implemented on clinical MR scanners for diffusion sensitization. (ajronline.org)
9 , 10 Diffusion anisotropy is most commonly quantified by the FA value. (ajnr.org)

The FA indirectly measures tissue organization (high FA corresponds to fibrous tissue with one orientation, and low FA is caused either by tissue disorganization such as in infiltration, by crossing fibers, or by high water content). (harvard.edu)
During the data analysis the measured dynamic structure factor S(Q,E) is fitted by a model function, which - reflecting the anisotropy of the sample - depends on the sample orientation. (epj.org)

For instance, our implementations include DKI-based microstructural models that allow the estimation of biophysical parameters, such as axonal water fraction. (frontiersin.org)
Optimal DTI parameters were b = 1000 mm/s 2 and 12 diffusion directions. (biomedcentral.com)

These estimates are of interest because they were shown to be more sensitive to microstructural alterations in health and diseases than measures based on the total anisotropy of diffusion which are highly confounded by tissue dispersion and fiber crossings. (frontiersin.org)

For the purpose of individual and group-wise analysis ( 3 ), several diffusion scalar measures can be further derived to better reveal the properties of that tensor. (frontiersin.org)

In fluorescence spectroscopy, the fluorescence anisotropy, calculated from the polarization properties of fluorescence from samples excited with plane-polarized light, is used, e.g., to determine the shape of a macromolecule. (everipedia.org)

The degree of diffusion weighting is described by the b value, a parameter that is determined by the type of sensitizing gradient scheme implemented in the MR experiment. (ajronline.org)

2004). "Alterations in water diffusion anisotropy indicate widespread cerebral white matter injury in premature infants. (edu.au)

In this work, we propose High Angular DTI Estimation Network (HADTI-Net) to estimate an enhanced DTI model from LARDI with a set of minimal and evenly distributed diffusion gradient directions. (frontiersin.org)
Extensive experiments have been conducted to show the reliability and generalisation of HADTI-Net to generate high angular DTI estimation from any minimal evenly distributed diffusion gradient directions and to explore the feasibility of applying a data-driven method for this task. (frontiersin.org)

Physicists from University of California, Berkeley reported about their detection of the cosine anisotropy in cosmic microwave background radiation in 1977. (everipedia.org)

By contrast, water diffuses faster along the Z axis (see the image below). (medscape.com)

Diffusion is termed isotropic if the motion is equal in all directions. (medscape.com)
This is sufficient for pathologies in areas such as gray matter, where diffusion is usually isotropic. (medscape.com)

We then review techniques for acquiring relatively high-resolution diffusion-sensitive MR images and computer-based algorithms that allow the generation of white matter fiber tract maps from the tensor data. (ajronline.org)
Once you have a proportional index map for each fiber pathway of interest you can multiply this weighting factor by the value of the diffusion measure (e.g. (diffusion-imaging.com)
Diffusion anisotropy varied widely among different white matter regions, reflecting differences in fiber-tract architecture. (ox.ac.uk)

Anatomy5

Diseases2

Chemicals and Drugs4

Analytical, Diagnostic and Therapeutic Techniques and Equipment11

Phenomena and Processes8

Disciplines and Occupations2

Information Science4

Health Care5

Fractional19

Rotational diffusion3

Brain22

Mean diffusivity2

Coefficient6

Anisotropic diffusion4

Tractography6

Motion of water molecules3

Molecules10

Imaging33

Directional2

Tracts4

Voxel1

Quantitative2

Magnitude of water diffusion2

Spatial2

Axial2

Multidimensional diffusion-relaxation1

Indices2

DMRI4

Metric3

Measurements2

Describe1

Characterization1

Tissues1

Characterize1

Gradients2

Abstract1

Acute1

Commonly2

Orientation2

Parameters2

Dispersion1

Reveal1

Fluorescence1

Degree1

Cerebral1

Angular2

Radiation1

Diffuses faster1

Isotropic2

Fiber3