Title
Weighted linear least squares estimation of diffusion MRI parameters : strengths, limitations, and pitfalls Weighted linear least squares estimation of diffusion MRI parameters : strengths, limitations, and pitfalls
Author
Faculty/Department
Faculty of Sciences. Physics
Publication type
article
Publication
New York ,
Subject
Physics
Human medicine
Computer. Automation
Source (journal)
Neuroimage. - New York
Volume/pages
81(2013) , p. 335-346
ISSN
1053-8119
ISI
000322934400033
Carrier
E
Target language
English (eng)
Full text (Publishers DOI)
Affiliation
University of Antwerp
Abstract
Purpose Linear least squares estimators are widely used in diffusion MRI for the estimation of diffusion parameters. Although adding proper weights is necessary to increase the precision of these linear estimators, there is no consensus on how to practically define them. In this study, the impact of the commonly used weighting strategies on the accuracy and precision of linear diffusion parameter estimators is evaluated and compared with the nonlinear least squares estimation approach. Methods Simulation and real data experiments were done to study the performance of the weighted linear least squares estimators with weights defined by (a) the squares of the respective noisy diffusion-weighted signals; and (b) the squares of the predicted signals, which are reconstructed from a previous estimate of the diffusion model parameters. Results The negative effect of weighting strategy (a) on the accuracy of the estimator was surprisingly high. Multi-step weighting strategies yield better performance and, in some cases, even outperformed the nonlinear least squares estimator. Conclusion If proper weighting strategies are applied, the weighted linear least squares approach shows high performance characteristics in terms of accuracy/precision and may even be preferred over nonlinear estimation methods.
E-info
https://repository.uantwerpen.be/docman/iruaauth/9cce20/24cbc53118a.pdf
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