Towards unconstrained compartment modeling in white matter using diffusion-relaxation MRI with tensor-valued diffusion encoding
(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.
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- author
- Lampinen, Björn LU ; Szczepankiewicz, Filip LU ; Mårtensson, Johan LU ; van Westen, Danielle LU ; Hansson, Oskar LU ; Westin, Carl Fredrik and Nilsson, Markus LU
- organization
- publishing date
- 2020-09
- 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
-
- pmid:32141131
- scopus:85080912830
- 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
- 2024-09-18 19:47:50
@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}}, }