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Tensor-valued diffusion MRI differentiates cortex and white matter in malformations of cortical development associated with epilepsy

Lampinen, Björn LU ; Zampeli, Ariadne LU ; Björkman-Burtscher, Isabella M. LU ; Szczepankiewicz, Filip LU orcid ; Källén, Kristina LU ; Compagno Strandberg, Maria LU and Nilsson, Markus LU (2020) In Epilepsia 61(8). p.1701-1713
Abstract

Objective: Delineation of malformations of cortical development (MCD) is central in presurgical evaluation of drug-resistant epilepsy. Delineation using magnetic resonance imaging (MRI) can be ambiguous, however, because the conventional T1- and T2-weighted contrasts depend strongly on myelin for differentiation of cortical tissue and white matter. Variations in myelin content within both cortex and white matter may cause MCD findings on MRI to change size, become undetectable, or disagree with histopathology. The novel tensor-valued diffusion MRI (dMRI) technique maps microscopic diffusion anisotropy, which is sensitive to axons rather than myelin. This work investigated whether tensor-valued dMRI may improve... (More)

Objective: Delineation of malformations of cortical development (MCD) is central in presurgical evaluation of drug-resistant epilepsy. Delineation using magnetic resonance imaging (MRI) can be ambiguous, however, because the conventional T1- and T2-weighted contrasts depend strongly on myelin for differentiation of cortical tissue and white matter. Variations in myelin content within both cortex and white matter may cause MCD findings on MRI to change size, become undetectable, or disagree with histopathology. The novel tensor-valued diffusion MRI (dMRI) technique maps microscopic diffusion anisotropy, which is sensitive to axons rather than myelin. This work investigated whether tensor-valued dMRI may improve differentiation of cortex and white matter in the delineation of MCD. Methods: Tensor-valued dMRI was performed on a 7 T MRI scanner in 13 MCD patients (age = 32 ± 13 years) featuring periventricular heterotopia, subcortical heterotopia, focal cortical dysplasia, and polymicrogyria. Data analysis yielded maps of microscopic anisotropy that were compared with T1-weighted and T2-fluid-attenuated inversion recovery images and with the fractional anisotropy from diffusion tensor imaging. Results: Maps of microscopic anisotropy revealed large white matter-like regions within MCD that were uniformly cortex-like in the conventional MRI contrasts. These regions were seen particularly in the deep white matter parts of subcortical heterotopias and near the gray-white boundaries of focal cortical dysplasias and polymicrogyrias. Significance: By being sensitive to axons rather than myelin, mapping of microscopic anisotropy may yield a more robust differentiation of cortex and white matter and improve MCD delineation in presurgical evaluation of epilepsy.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
axons, microscopic diffusion anisotropy, myelin
in
Epilepsia
volume
61
issue
8
pages
13 pages
publisher
Wiley-Blackwell
external identifiers
  • scopus:85087923068
  • pmid:32667688
ISSN
0013-9580
DOI
10.1111/epi.16605
language
English
LU publication?
yes
id
37ee07d9-a7e8-48b4-8533-0b6cabe3ec18
date added to LUP
2020-07-27 15:23:26
date last changed
2024-05-15 15:17:39
@article{37ee07d9-a7e8-48b4-8533-0b6cabe3ec18,
  abstract     = {{<p>Objective: Delineation of malformations of cortical development (MCD) is central in presurgical evaluation of drug-resistant epilepsy. Delineation using magnetic resonance imaging (MRI) can be ambiguous, however, because the conventional T<sub>1</sub>- and T<sub>2</sub>-weighted contrasts depend strongly on myelin for differentiation of cortical tissue and white matter. Variations in myelin content within both cortex and white matter may cause MCD findings on MRI to change size, become undetectable, or disagree with histopathology. The novel tensor-valued diffusion MRI (dMRI) technique maps microscopic diffusion anisotropy, which is sensitive to axons rather than myelin. This work investigated whether tensor-valued dMRI may improve differentiation of cortex and white matter in the delineation of MCD. Methods: Tensor-valued dMRI was performed on a 7 T MRI scanner in 13 MCD patients (age = 32 ± 13 years) featuring periventricular heterotopia, subcortical heterotopia, focal cortical dysplasia, and polymicrogyria. Data analysis yielded maps of microscopic anisotropy that were compared with T<sub>1</sub>-weighted and T<sub>2</sub>-fluid-attenuated inversion recovery images and with the fractional anisotropy from diffusion tensor imaging. Results: Maps of microscopic anisotropy revealed large white matter-like regions within MCD that were uniformly cortex-like in the conventional MRI contrasts. These regions were seen particularly in the deep white matter parts of subcortical heterotopias and near the gray-white boundaries of focal cortical dysplasias and polymicrogyrias. Significance: By being sensitive to axons rather than myelin, mapping of microscopic anisotropy may yield a more robust differentiation of cortex and white matter and improve MCD delineation in presurgical evaluation of epilepsy.</p>}},
  author       = {{Lampinen, Björn and Zampeli, Ariadne and Björkman-Burtscher, Isabella M. and Szczepankiewicz, Filip and Källén, Kristina and Compagno Strandberg, Maria and Nilsson, Markus}},
  issn         = {{0013-9580}},
  keywords     = {{axons; microscopic diffusion anisotropy; myelin}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{8}},
  pages        = {{1701--1713}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Epilepsia}},
  title        = {{Tensor-valued diffusion MRI differentiates cortex and white matter in malformations of cortical development associated with epilepsy}},
  url          = {{http://dx.doi.org/10.1111/epi.16605}},
  doi          = {{10.1111/epi.16605}},
  volume       = {{61}},
  year         = {{2020}},
}