Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Towards unconstrained compartment modeling in white matter using diffusion-relaxation MRI with tensor-valued diffusion encoding

Lampinen, Björn LU ; Szczepankiewicz, Filip LU orcid ; Mårtensson, Johan LU ; van Westen, Danielle LU orcid ; Hansson, Oskar LU orcid ; Westin, Carl Fredrik and Nilsson, Markus LU (2020) In Magnetic Resonance in Medicine 84(3). p.1605-1623
Abstract

Purpose: To optimize diffusion-relaxation MRI with tensor-valued diffusion encoding for precise estimation of compartment-specific fractions, diffusivities, and T2 values within a two-compartment model of white matter, and to explore the approach in vivo. Methods: Sampling protocols featuring different b-values (b), b-tensor shapes (bΔ), and echo times (TE) were optimized using Cramér-Rao lower bounds (CRLB). Whole-brain data were acquired in children, adults, and elderly with white matter lesions. Compartment fractions, diffusivities, and T2 values were estimated in a model featuring two microstructural compartments represented by a “stick” and a “zeppelin.”. Results: Precise parameter estimates were... (More)

Purpose: To optimize diffusion-relaxation MRI with tensor-valued diffusion encoding for precise estimation of compartment-specific fractions, diffusivities, and T2 values within a two-compartment model of white matter, and to explore the approach in vivo. Methods: Sampling protocols featuring different b-values (b), b-tensor shapes (bΔ), and echo times (TE) were optimized using Cramér-Rao lower bounds (CRLB). Whole-brain data were acquired in children, adults, and elderly with white matter lesions. Compartment fractions, diffusivities, and T2 values were estimated in a model featuring two microstructural compartments represented by a “stick” and a “zeppelin.”. Results: Precise parameter estimates were enabled by sampling protocols featuring seven or more “shells” with unique b/bΔ/TE-combinations. Acquisition times were approximately 15 minutes. In white matter of adults, the “stick” compartment had a fraction of approximately 0.5 and, compared with the “zeppelin” compartment, featured lower isotropic diffusivities (0.6 vs. 1.3 μm2/ms) but higher T2 values (85 vs. 65 ms). Children featured lower “stick” fractions (0.4). White matter lesions exhibited high “zeppelin” isotropic diffusivities (1.7 μm2/ms) and T2 values (150 ms). Conclusions: Diffusion-relaxation MRI with tensor-valued diffusion encoding expands the set of microstructure parameters that can be precisely estimated and therefore increases their specificity to biological quantities.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
brain microstructure, diffusion-relaxation MRI, Fisher information, tensor-valued diffusion encoding
in
Magnetic Resonance in Medicine
volume
84
issue
3
pages
19 pages
publisher
John Wiley & Sons Inc.
external identifiers
  • scopus:85080912830
  • pmid:32141131
ISSN
0740-3194
DOI
10.1002/mrm.28216
language
English
LU publication?
yes
id
cf529d6b-1f6d-4ee4-928f-12a8616feb45
date added to LUP
2020-03-19 15:39:14
date last changed
2024-06-27 14:40:05
@article{cf529d6b-1f6d-4ee4-928f-12a8616feb45,
  abstract     = {{<p>Purpose: To optimize diffusion-relaxation MRI with tensor-valued diffusion encoding for precise estimation of compartment-specific fractions, diffusivities, and T<sub>2</sub> values within a two-compartment model of white matter, and to explore the approach in vivo. Methods: Sampling protocols featuring different b-values (b), b-tensor shapes (b<sub>Δ</sub>), and echo times (TE) were optimized using Cramér-Rao lower bounds (CRLB). Whole-brain data were acquired in children, adults, and elderly with white matter lesions. Compartment fractions, diffusivities, and T<sub>2</sub> values were estimated in a model featuring two microstructural compartments represented by a “stick” and a “zeppelin.”. Results: Precise parameter estimates were enabled by sampling protocols featuring seven or more “shells” with unique b/b<sub>Δ</sub>/TE-combinations. Acquisition times were approximately 15 minutes. In white matter of adults, the “stick” compartment had a fraction of approximately 0.5 and, compared with the “zeppelin” compartment, featured lower isotropic diffusivities (0.6 vs. 1.3 μm<sup>2</sup>/ms) but higher T<sub>2</sub> values (85 vs. 65 ms). Children featured lower “stick” fractions (0.4). White matter lesions exhibited high “zeppelin” isotropic diffusivities (1.7 μm<sup>2</sup>/ms) and T<sub>2</sub> values (150 ms). Conclusions: Diffusion-relaxation MRI with tensor-valued diffusion encoding expands the set of microstructure parameters that can be precisely estimated and therefore increases their specificity to biological quantities.</p>}},
  author       = {{Lampinen, Björn and Szczepankiewicz, Filip and Mårtensson, Johan and van Westen, Danielle and Hansson, Oskar and Westin, Carl Fredrik and Nilsson, Markus}},
  issn         = {{0740-3194}},
  keywords     = {{brain microstructure; diffusion-relaxation MRI; Fisher information; tensor-valued diffusion encoding}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{1605--1623}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Magnetic Resonance in Medicine}},
  title        = {{Towards unconstrained compartment modeling in white matter using diffusion-relaxation MRI with tensor-valued diffusion encoding}},
  url          = {{http://dx.doi.org/10.1002/mrm.28216}},
  doi          = {{10.1002/mrm.28216}},
  volume       = {{84}},
  year         = {{2020}},
}