scholarly journals Diffusion-weighted MRI of hepatic tumor in rats: Comparison between in vivo and postmortem imaging acquisitions

2009 ◽  
Vol 29 (3) ◽  
pp. 621-628 ◽  
Author(s):  
Xihe Sun ◽  
Huaijun Wang ◽  
Feng Chen ◽  
Frederik De Keyzer ◽  
Jie Yu ◽  
...  
Keyword(s):  
Hepatic Tumor ◽  
Diffusion Weighted Mri ◽  
Postmortem Imaging ◽  
Diffusion Weighted

Diffusion-Weighted MRI Used to Detect in Vivo Modulation of Cortical Spreading Depression: Comparison of Sumatriptan and Tonabersat

2001 ◽  
Vol 172 (2) ◽  
pp. 342-353 ◽  
Author(s):  
Daniel P. Bradley ◽  
Martin I. Smith ◽  
Chaiyapoj Netsiri ◽  
Justin M. Smith ◽  
Kurt H.J. Bockhorst ◽  
...  
Keyword(s):  
Cortical Spreading Depression ◽  
Spreading Depression ◽  
Diffusion Weighted Mri ◽  
Diffusion Weighted

629: The use of diffusion-weighted MRI to study in-vivo fetal lung maturation in a rabbit model

2008 ◽  
Vol 199 (6) ◽  
pp. S181
Author(s):  
Scott Petersen ◽  
Ronald Peeters ◽  
Frederik De Keyzer ◽  
Jan Deprest ◽  
Filip Claus
Keyword(s):  
Rabbit Model ◽  
Fetal Lung ◽  
Diffusion Weighted Mri ◽  
Lung Maturation ◽  
Diffusion Weighted ◽  
Fetal Lung Maturation

scholarly journals Direction-Averaged Diffusion-Weighted MRI Signal using different Axisymmetric B-tensor Encoding Schemes “Submitted to Magnetic Resonance in Medicine”

2019 ◽  
Author(s):  
Maryam Afzali ◽  
Santiago Aja-Fernández ◽  
Derek K Jones
Keyword(s):  
Power Law ◽  
In Silico ◽  
Complete Analysis ◽  
Diffusion Weighted Mri ◽  
B Values ◽  
Diffusion Geometry ◽  
In Vivo Experiments ◽  
Diffusion Weighted ◽  
Wave Forms

AbstractPurposeIt has been shown previously that for the conventional Stejskal-Tanner pulsed gradient, or linear tensor encoding (LTE), as well as planar tensor encoding (PTE) and in tissue in which diffusion exhibits a ‘stick-like’ geometry, the diffusion-weighted MRI signal at extremely high b-values follows a power-law. Specifically, the signal decays as a in LTE and 1/b in PTE. Here, the direction-averaged signal for arbitrary diffusion encoding waveforms is considered to establish whether power-law behaviors occur with other encoding wave-forms and for other (non-stick-like) diffusion geometries.MethodsWe consider the signal decay for high b-values for encoding geometries ranging from 2-dimensional planar tensor encoding (PTE), through isotropic or spherical tensor encoding (STE) to linear tensor encoding. When a power-law behavior was suggested, this was tested using in-silico simulations and in-vivo using an ultra-strong gradient (300 mT/m) Connectom scanner.ResultsThe results show that using an axisymmetric b-tensor a power-law only exists for two scenarios: For stick-like geometries, (i) the already-discovered LTE case; and (ii) for pure planar encoding. In this latter case, to first order, the signal decays as 1/b. Our in-silico and in-vivo experiments confirm this 1/b relationship.ConclusionA complete analysis of the power-law dependencies of the diffusion-weighted signal at high b-values has been performed. Only two forms of encoding result in a power-law dependency, pure linear and pure planar tensor encoding and when the diffusion geometry is ‘stick-like’. The different exponents of these encodings could be used to provide independent validation of the presence of stick-like geometries in-vivo.

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