RT info:eu-repo/semantics/article
T1 Accurate free‐water estimation in white matter from fast diffusion MRI acquisitions using the spherical means technique
A1 Tristán Vega, Antonio
A1 París l Bandrés, Guillem Lluis
A1 Luis García, Rodrigo de
A1 Aja Fernández, Santiago
K1 Diffusion MRI
K1 Free water
K1 Spherical means
K1 White matter
K1 22 Física
AB To accurately estimate the partial volume fraction of free water in the white matter from diffusion MRI acquisitions not demanding strong sensitizing gradients and/or large collections of different b-values. Data sets considered comprise~32- 64 gradients near b =1000 s/mm2 plus~6 gradients near b =500 s/mm2.Theory and Methods: The spherical means of each diffusion MRI set with the same b- value are computed. These means are related to the inherent diffusion parameters within the voxel (free-  and cellular- water fractions; cellular- water diffusivity), which are solved by constrained nonlinear least squares regression.Results:  The proposed method outperforms those based on mixtures of two Gaussians for the kind of data sets considered. W.r.t. the accuracy, the former does not introduce significant biases in the scenarios of interest, while the latter can reach a bias of 5%– 7% if fiber crossings are present. W.r.t. the precision, a variance near 10%, compared to 15%, can be attained for usual configurations.Conclusion: It is possible to compute reliable estimates of the free- water fraction inside the white matter by complementing typical DTI acquisitions with few gradients at a lowb- value. It can be done voxel- by- voxel, without imposing spatial regularity constraints.
PB Wiley
SN 0740-3194
YR 2021
FD 2021
LK https://uvadoc.uva.es/handle/10324/49001
UL https://uvadoc.uva.es/handle/10324/49001
LA eng
NO Magnetic Resonance in Medicine, 2021, vol 00, p.1-8
NO Producción Científica
DS UVaDOC
RD 24-nov-2024