scholarly journals Fiber orientation distribution from diffusion MRI: Effects of inaccurate response function calibration

2021 ◽  
Author(s):  
Fenghua Guo ◽  
Chantal M. W. Tax ◽  
Alberto De Luca ◽  
Max A. Viergever ◽  
Anneriet Heemskerk ◽  
...  
Keyword(s):  
Response Function ◽  
Fiber Orientation ◽  
Diffusion Mri ◽  
Orientation Distribution ◽  
Fiber Orientation Distribution

scholarly journals Effects of Inaccurate Response Function Calibration on Characteristics of the Fiber Orientation Distribution in Diffusion MRI

2019 ◽  
Author(s):  
Fenghua Guo ◽  
Chantal M.W. Tax ◽  
Alberto De Luca ◽  
Max A. Viergever ◽  
Anneriet Heemskerk ◽  
...  
Keyword(s):  
Response Function ◽  
Fiber Orientation ◽  
Shape Factor ◽  
Diffusion Mri ◽  
Orientation Distribution ◽  
Fiber Tracking ◽  
Fiber Tractography ◽  
Scaling Factors ◽  
Spherical Deconvolution ◽  
Fiber Orientation Distribution

AbstractDiffusion MRI of the brain enables to quantify white matter fiber orientations noninvasively. Several approaches have been proposed to estimate such characteristics from diffusion MRI data with spherical deconvolution being one of the most widely used methods. Constrained spherical deconvolution requires to define – or derive from the data – a response function, which is used to compute the fiber orientation distribution (FOD). This definition or derivation is not unequivocal and can thus result in different characteristics of the response function which are expected to affect the FOD computation and the subsequent fiber tracking. In this work, we explored the effects of inaccuracies in the shape and scaling factors of the response function on the FOD characteristics. With simulations, we show that underestimation of the shape factor in the response functions has a larger effect on the FOD peaks than overestimation of the shape factor, whereas the latter will cause more spurious peaks. Moreover, crossing fiber populations with a smaller separation angle were more sensitive to the response function inaccuracy than fiber populations with more orthogonal separation angles. Furthermore, the FOD characteristics show deviations as a result of modified shape and scaling factors of the response function. Results with the in vivo data demonstrate that the deviations of the FODs and spurious peaks can further deviate the termination of propagation in fiber tracking. This work highlights the importance of proper definition of the response function and how specific calibration factors can affect the FOD and fiber tractography results.

scholarly journals Axon diameter index estimation independent of fiber orientation distribution using high-gradient diffusion MRI

NeuroImage ◽  
2020 ◽  
Vol 222 ◽  
pp. 117197 ◽  
Author(s):  
Qiuyun Fan ◽  
Aapo Nummenmaa ◽  
Thomas Witzel ◽  
Ned Ohringer ◽  
Qiyuan Tian ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Diffusion Mri ◽  
Orientation Distribution ◽  
Axon Diameter ◽  
High Gradient ◽  
Gradient Diffusion ◽  
Fiber Orientation Distribution ◽  
Index Estimation

scholarly journals Fast Fiber Orientation Estimation in Diffusion MRI from kq-Space Sampling and Anatomical Priors

2021 ◽  
Vol 7 (11) ◽  
pp. 226
Author(s):  
Marica Pesce ◽  
Audrey Repetti ◽  
Anna Auría ◽  
Alessandro Daducci ◽  
Jean-Philippe Thiran ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Diffusion Mri ◽  
Angular Resolution ◽  
Real Data ◽  
Orientation Distribution ◽  
Accurate Identification ◽  
Fiber Orientation Distribution ◽  
Under Sampling ◽  
The Cost ◽  
Anatomical Priors

High spatio-angular resolution diffusion MRI (dMRI) has been shown to provide accurate identification of complex neuronal fiber configurations, albeit, at the cost of long acquisition times. We propose a method to recover intra-voxel fiber configurations at high spatio-angular resolution relying on a 3D kq-space under-sampling scheme to enable accelerated acquisitions. The inverse problem for the reconstruction of the fiber orientation distribution (FOD) is regularized by a structured sparsity prior promoting simultaneously voxel-wise sparsity and spatial smoothness of fiber orientation. Prior knowledge of the spatial distribution of white matter, gray matter, and cerebrospinal fluid is also leveraged. A minimization problem is formulated and solved via a stochastic forward–backward algorithm. Simulations and real data analysis suggest that accurate FOD mapping can be achieved from severe kq-space under-sampling regimes potentially enabling high spatio-angular resolution dMRI in the clinical setting.

Effect of Fiber Orientation on the Tensile Strength in Fiber-Reinforced Polymeric Composite Materials

2005 ◽  
Vol 297-300 ◽  
pp. 2897-2902 ◽  
Author(s):  
Jin Woo Kim ◽  
Jung Ju Lee ◽  
Dong Gi Lee
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Fiber Orientation ◽  
Polymeric Composite ◽  
Orientation Distribution ◽  
Fiber Content ◽  
Fiber Reinforced ◽  
Composite Sheet ◽  
Content Ratio ◽  
Fiber Orientation Distribution

The study for strength calculation of one way fiber-reinforced composites and the study measuring precisely fiber orientation distribution were presented. However, because the DB that can predict mechanical properties of composite material and fiber orientation distribution by the fiber content ratio was not constructed, we need the systematic study for that. Therefore, in this study, we investigated what effect the fiber content ratio and fiber orientation distribution have on the strength of composite sheet after making fiber reinforced polymeric composite sheet by changing fiber orientation distribution with the fiber content ratio. The result of this study will become a guide to design data of the most suitable parts design or fiber reinforced polymeric composite sheet that uses the fiber reinforced polymeric composite sheet in industry spot, because it was conducted in terms of developing products. We studied the effect the fiber orientation distribution has on tensile strength of fiber reinforced polymeric composite material and achieved this results below. We can say that the increasing range of the value of fiber reinforced polymeric composite’s tensile strength in the direction of fiber orientation is getting wider as the fiber content ratio increases. It shows that the value of fiber reinforced polymeric composite’s tensile strength in the direction of fiber orientation 90° is similar with the value of polypropylene’s intensity when fiber orientation function is J= 0.7, regardless of the fiber content ratio. Tensile strength of fiber reinforced polymeric composite is affected by the fiber orientation distribution more than by the fiber content ratio.

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