Filters








3,302 Hits in 5.0 sec

Efficient Computation of PDF-Based Characteristics from Diffusion MR Signal [chapter]

Haz-Edine Assemlal, David Tschumperlé, Luc Brun
2008 Lecture Notes in Computer Science  
The approach relies on the approximation of the MR signal by a series expansion based on Spherical Harmonics and Laguerre-Gaussian functions, followed by a simple projection step that is efficiently done  ...  We present a general method for the computation of PDFbased characteristics of the tissue micro-architecture in MR imaging.  ...  Estimation of PDF-Based Characteristics The estimation of the PDF from Eq.(1) is a trade-off between the number of samples and the prior on the MR signal, so we introduce an orthonormal basis based on  ... 
doi:10.1007/978-3-540-85990-1_9 fatcat:w6xaj6kyezcfhhumbe2cclmlpm

Efficient computation of PDF-based characteristics from diffusion MR signal

Haz-Edine Assemlal, David Tschumperlé, Luc Brun
2008
We present a general method for the computation of PDF-based characteristics of the tissue micro-architecture in MR imaging.  ...  The approach relies on the approximation of the MR signal by a series expansion based on Spherical Harmonics and Laguerre-Gaussian functions, followed by a simple projection step that is efficiently done  ...  Estimation of PDF-Based Characteristics The estimation of the PDF from Eq.(1) is a trade-off between the number of samples and the prior on the MR signal, so we introduce an orthonormal basis based on  ... 
pmid:18982591 fatcat:lnsvr5jnsbe25lddxwpatu52qi

Review on: Image De-noising using Bilateral Filter with Multilinear Discriminant Analysis and SVM

Rohit Jaspal, Amandeep Ummat
2015 International Journal of Computer Applications  
The quantitative analysis based on the standard metrics like peak signal-to-noise ratio and mean structural similarity index matrix.  ...  It improves the denoising efficiency. It also preserves the fine structures of the image. It also reduces the bias due to Rician noise. Thus we can preserve the quality of image.  ...  Thus main advantage of this method is its capability to compute signals with a smooth change in the intensity value.  ... 
doi:10.5120/21030-2887 fatcat:kz22udymwnf5zjeawxwdqaqrwa

Adaptive anisotropic noise filtering for magnitude MR data

J. Sijbers, A.J. den Dekker, A. Van der Linden, M. Verhoye, D. Van Dyck
1999 Magnetic Resonance Imaging  
Conventional noise filtering schemes applied to magnitude magnetic resonance (MR) images tacitly assume Gauss distributed noise. Magnitude MR data, however, are Rice distributed.  ...  Not incorporating this knowledge leads inevitably to biased results, in particular when applying such filters in regions with low signal-to-noise ratio.  ...  Acknowledgements This work was financially supported by the Flemish institute for the promotion of scientific and technological research in the industry (IWT), Brussels.  ... 
doi:10.1016/s0730-725x(99)00088-0 pmid:10610003 fatcat:xx6me53o4jekbib7ltcd4jqwrm

Adaptive anisotropic noise filtering for magnitude MR data

Jan Sijbers, Arnold J. den Dekker, Marleen Verhoye, Anne-Marie Van der Linden, Dirk Van Dyck, Kenneth M. Hanson
1999 Medical Imaging 1999: Image Processing  
Conventional noise filtering schemes applied to magnitude magnetic resonance (MR) images tacitly assume Gauss distributed noise. Magnitude MR data, however, are Rice distributed.  ...  Not incorporating this knowledge leads inevitably to biased results, in particular when applying such filters in regions with low signal-to-noise ratio.  ...  Acknowledgements This work was financially supported by the Flemish institute for the promotion of scientific and technological research in the industry (IWT), Brussels.  ... 
doi:10.1117/12.348541 dblp:conf/miip/SijbersDVLD99 fatcat:5sd5swvmnbhjxbbvltoou2hamq

A CONTINUOUS MIXTURE OF TENSORS MODEL FOR DIFFUSION-WEIGHTED MR SIGNAL RECONSTRUCTION

Bing Jian, Baba Vemuri, Evren Ozarslan, Paul Carney, Thomas Mareci
2007 2007 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro  
In this paper, we present a novel statistical model which describes the diffusion-attenuated MR signal by the Laplace transform of a probability distribution over symmetric positive definite matrices.  ...  We also develop an efficient scheme for reconstructing the multiple fiber bundles from the DW-MRI measurements.  ...  The simulations employed the exact form of the MR signal attenuation from particles diffusing inside cylindrical boundaries [13] .  ... 
doi:10.1109/isbi.2007.356966 pmid:19936041 pmcid:PMC2779041 dblp:conf/isbi/JianVOCM07 fatcat:bkdggj3b2jg3pocah5ew4knd4i

Symmetric Positive-Definite Cartesian Tensor Orientation Distribution Functions (CT-ODF) [chapter]

Yonas T. Weldeselassie, Angelos Barmpoutis, M. Stella Atkins
2010 Lecture Notes in Computer Science  
A novel method for estimating a field of orientation distribution functions (ODF) from a given set of DW-MR images is presented.  ...  We quantitatively evaluate our method using simulated DW-MR images as well as a real brain dataset from a post-mortem porcine brain.  ...  MR signals.  ... 
doi:10.1007/978-3-642-15705-9_71 fatcat:llbampkezzfcnavrw7g5op66cq

Accelerated Diffusion Spectrum Imaging with Compressed Sensing Using Adaptive Dictionaries [chapter]

Berkin Bilgic, Kawin Setsompop, Julien Cohen-Adad, Van Wedeen, Lawrence L. Wald, Elfar Adalsteinsson
2012 Lecture Notes in Computer Science  
Further, we demonstrate that a dictionary trained using pdfs from a single slice of a particular subject generalizes well to other slices from the same subject, as well as to slices from another subject  ...  It is possible to accelerate DSI by sub-Nyquist sampling of the q-space followed by nonlinear reconstruction to estimate the diffusion probability density functions (pdfs).  ...  While prespecified transformations such as wavelets and spatial gradients yield sparse signal representation, tailoring the sparsifying transform based on the characteristics of the particular signal type  ... 
doi:10.1007/978-3-642-33454-2_1 fatcat:gd4pvtuzqzeypon35w7cafuguq

Characterization and propagation of uncertainty in diffusion-weighted MR imaging

T.E.J. Behrens, M.W. Woolrich, M. Jenkinson, H. Johansen-Berg, R.G. Nunes, S. Clare, P.M. Matthews, J.M. Brady, S.M. Smith
2003 Magnetic Resonance in Medicine  
This technique is applied to the estimation of parameters in the diffusion tensor model, and also to a simple partial volume model of diffusion.  ...  A fully probabilistic framework is presented for estimating local probability density functions on parameters of interest in a model of diffusion.  ...  ACKNOWLEDGMENTS The authors thank Claudia Wheeler-Kingshott, Phil Boulby, and Gareth Barker from the Institute of Neurology, Queen's Square, London, and the UK Multiple Sclerosis Society for providing  ... 
doi:10.1002/mrm.10609 pmid:14587019 fatcat:tycnav25yve4nontjmpl42jrza

Removal of intensity bias in magnitude spin-echo MRI images by nonlinear diffusion filtering

Alexei A. Samsonov, Chris R. Johnson, J. Michael Fitzpatrick, Milan Sonka
2004 Medical Imaging 2004: Image Processing  
The incorporation of the Rice PDF into a noise filtering procedure can significantly complicate the method both algorithmically and computationally.  ...  In our proposed method, the separate diffusion processes are coupled through combined diffusion coefficients determined from the image magnitude.  ...  Such noise could be efficiently eliminated using filtering procedures based on spatial averaging.  ... 
doi:10.1117/12.535899 dblp:conf/miip/SamsonovJ04 fatcat:25htf4yyjvc4zpcv6irc3agr4y

Optimal diffusion MRI acquisition for fiber orientation density estimation: An analytic approach

Nathan S. White, Anders M. Dale
2009 Human Brain Mapping  
An important challenge in the design of diffusion MRI experiments is how to optimize statistical efficiency, i.e., the accuracy with which parameters can be estimated from the diffusion data in a given  ...  In model-based spherical deconvolution analysis, the quantity of interest is the fiber orientation density (FOD).  ...  Diffusion spectrum imaging (DSI) provides a direct quantification of the water diffusion PDF by exploiting the Fourier relationship between the PDF and the normalized diffusion signal (Wedeen, et al.  ... 
doi:10.1002/hbm.20799 pmid:19603409 pmcid:PMC3367885 fatcat:qgvkq4x3nzgnvn62ejse52dgem

Accelerated MR diffusion tensor imaging using distributed compressed sensing

Yin Wu, Yan-Jie Zhu, Qiu-Yang Tang, Chao Zou, Wei Liu, Rui-Bin Dai, Xin Liu, Ed X. Wu, Leslie Ying, Dong Liang
2013 Magnetic Resonance in Medicine  
Purpose: Diffusion tensor imaging (DTI) is known to suffer from long acquisition time in the orders of several minutes or even hours.  ...  Reconstruction performance with varied signal-to-noise ratio and acceleration factors were evaluated by root-mean-square error and maps of reconstructed DTI indices.  ...  By exploiting the redundancy across multiple signals, acceleration beyond only using sparsity of a single signal could be achieved more efficiently (44, 45) .  ... 
doi:10.1002/mrm.24721. pmid:23494999 fatcat:764txzncbjhchabuqzivdlvydu

A novel tensor distribution model for the diffusion-weighted MR signal

Bing Jian, Baba C. Vemuri, Evren Özarslan, Paul R. Carney, Thomas H. Mareci
2007 NeuroImage  
In this paper, we present a novel statistical model for diffusion-weighted MR signal attenuation which postulates that the water molecule diffusion can be characterized by a continuous mixture of diffusion  ...  An interesting observation is that this continuous mixture and the MR signal attenuation are related through the Laplace transform of a probability distribution over symmetric positive definite matrices  ...  Introduction Diffusion-weighted imaging (DWI) is a magnetic resonance (MR) technique exploiting the sensitivity of the MR signal to the Brownian motion of water molecules.  ... 
doi:10.1016/j.neuroimage.2007.03.074 pmid:17570683 pmcid:PMC2576290 fatcat:6anah7gnebapphw37kgdnkucdi

Denoising of DT-MR Images with an Iterative PCA

U. Sreelakshmi Priya, Jyothisha J. Nair
2015 Procedia Computer Science  
Currently most of the clinical application uses Diffusion Tensor-MR Images for tracking neural fibres by extracting features from the images.  ...  Noise in DT-MR Images make fibre tracking and disease diagnosing tougher. So our work aims to denoise the Diffusion Tensor MR images with better visual quality.  ...  Sandhya Harikumar, and Mrs. Geetha M, Department of Computer Science for their valuable suggestions.  ... 
doi:10.1016/j.procs.2015.08.079 fatcat:dptqhcgwt5h23a6qos5oh5tdca

Probing white-matter microstructure with higher-order diffusion tensors and susceptibility tensor MRI

Chunlei Liu, Nicole E. Murphy, Wei Li
2013 Frontiers in Integrative Neuroscience  
Diffusion properties were quantified with the diffusion tensor model and also with the higher order tensor model based on the cumulant expansion.  ...  It is believed that diffusion MRI and susceptibility MRI provide complementary information of the microstructure of white matter.  ...  ., for providing the phantom diffusion data. The study was supported in part by the National Institutes of Health through grant R00EB007182.  ... 
doi:10.3389/fnint.2013.00011 pmid:23507987 pmcid:PMC3589706 fatcat:w26yna37mfbvrdky7yyyfqxfau
« Previous Showing results 1 — 15 out of 3,302 results