Life Sciences & Biomedicine Neuroimaging Neurosciences Neurosciences & Neurology Radiology, Nuclear Medicine & Medical Imaging Science & Technology
In Diffusion Weighted Magnetic Resonance Image (DW-MRI) processing, a 2nd order tensor has been commonly used to approximate the diffusivity function at each lattice point of the DW-MRI data. From this tensor approximation, one can compute useful scalar quantities (e. g. anisotropy, mean diffusivity) which have been clinically used for monitoring encephalopathy, sclerosis, ischemia and other brain disorders. It is now well known that this 2nd-order tensor approximation fails to capture complex local tissue structures, e. g. crossing fibers, and as a result, the scalar quantities derived from these tensors are grossly inaccurate at such locations. In this paper we employ a 4th order symmetric positive-definite (SPD) tensor approximation to represent the diffusivity function and present a novel technique to estimate these tensors from the DW-MRI data guaranteeing the SPD property. Several articles have been reported in literature on higher order tensor approximations of the diffusivity function but none of them guarantee the positivity of the estimates, which is a fundamental constraint since negative values of the diffusivity are not meaningful. In this paper we represent the 4th-order tensors as ternary quartics and then apply Hilbert's theorem on ternary quartics along with the Iwasawa parametrization to guarantee an SPD 4th-order tensor approximation from the DW-MRI data. The performance of this model is depicted on synthetic data as well as real DW-MRIs from a set of excised control and injured rat spinal cords, showing accurate estimation of scalar quantities such as generalized anisotropy and trace as well as fiber orientations. (C) 2008 Elsevier Inc. All rights reserved.
Regularized positive-definite fourth order tensor field estimation from DW-MRI
Creators
Angelos Barmpoutis - University of Florida
Min Sig Hwang - University of Florida
Dena Howland - University of Florida
John R. Forder - University of Florida
Baba C. Vemuri - University of Florida
Publication Details
NeuroImage (Orlando, Fla.), v 45(1), pp S153-S162
Publisher
Elsevier
Number of pages
10
Grant note
R01 EB007082-03; R01 EB007082; R01 EB007082-04; EB007082 / NIBIB NIH HHS; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Institute of Biomedical Imaging & Bioengineering (NIBIB)
R01EB007082 / NATIONAL INSTITUTE OF BIOMEDICAL IMAGING AND BIOENGINEERING; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Institute of Biomedical Imaging & Bioengineering (NIBIB)
Resource Type
Journal article
Language
English
Academic Unit
Radiation Oncology (and Nuclear Medicine)
Web of Science ID
WOS:000263862600014
Scopus ID
2-s2.0-65549135890
Other Identifier
991021897485704721
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Web of Science research areas
Neuroimaging
Neurosciences
Radiology, Nuclear Medicine & Medical Imaging
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