Multi-parametric quantitative MRI reveals three different white matter subtypes

Jack R Foucher; Olivier Mainberger; Julien Lamy; Mathieu D Santin; Alexandre Vignaud; Mathilde M Roser; Paulo L de Sousa

doi:10.1371/journal.pone.0196297

Multi-parametric quantitative MRI reveals three different white matter subtypes

PLoS One. 2018 Jun 15;13(6):e0196297. doi: 10.1371/journal.pone.0196297. eCollection 2018.

Authors

Jack R Foucher^{1

2

3

4}, Olivier Mainberger^{1

2

3

4}, Julien Lamy^{1

2}, Mathieu D Santin⁵, Alexandre Vignaud⁶, Mathilde M Roser^{1

2

3

4}, Paulo L de Sousa^{1

2}

Affiliations

¹ Laboratoire des Sciences de l'Ingénieur, de l'Informatique et de l'Imagerie (ICube), CNRS UMR 7357, University of Strasbourg, Strasbourg, France.
² Fédération de Médecine Translationnelle de Strasbourg (FMTS), University of Strasbourg, Strasbourg, France.
³ CEntre de neuroModulation Non Invasive de Strasbourg (CEMNIS), University Hospital, Strasbourg, France.
⁴ Department of Physiology, University of Strasbourg, Strasbourg, France.
⁵ CENIR, ICM, Paris, France.
⁶ CEA, I2BM, NeuroSpin, UNIRS, Gif-sur-Yvette, France.

Abstract

Introduction: Magnetic resonance imaging (MRI) shows slight spatial variations in brain white matter (WM). We used quantitative multi-parametric MRI to evaluate in what respect these inhomogeneities could correspond to WM subtypes with specific characteristics and spatial distribution.

Materials and methods: Twenty-six controls (12 women, 38 ±9 Y) took part in a 60-min session on a 3T scanner measuring 7 parameters: R1 and R2, diffusion tensor imaging which allowed to measure Axial and Radial Diffusivity (AD, RD), magnetization transfer imaging which enabled to compute the Macromolecular Proton Fraction (MPF), and a susceptibility-weighted sequence which permitted to quantify R2* and magnetic susceptibility (χm). Spatial independent component analysis was used to identify WM subtypes with specific combination of quantitative parameters values.

Results: Three subtypes could be identified. t-WM (track) mostly mapped on well-formed projection and commissural tracts and came with high AD values (all p < 10(-18)). The two other subtypes were located in subcortical WM and overlapped with association fibers: f-WM (frontal) was mostly anterior in the frontal lobe whereas c-WM (central) was underneath the central cortex. f-WM and c-WM had higher MPF values, indicating a higher myelin content (all p < 1.7 10(-6)). This was compatible with their larger χm and R2, as iron is essentially stored in oligodendrocytes (all p < 0.01). Although R1 essentially showed the same, its higher value in t-WM relative to c-WM might be related to its higher cholesterol concentration.

Conclusions: Thus, f- and c-WMs were less structured, but more myelinated and probably more metabolically active regarding to their iron content than WM related to fasciculi (t-WM). As known WM bundles passed though different WM subtypes, myelination might not be uniform along the axons but rather follow a spatially consistent regional variability. Future studies might examine the reproducibility of this decomposition and how development and pathology differently affect each subtype.

Publication types

Clinical Trial
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Diffusion Tensor Imaging*
Female
Humans
Magnetic Resonance Imaging*
Male
Middle Aged
White Matter / diagnostic imaging*

Associated data

figshare/10.6084/m9.figshare.5946781

Grants and funding

This work was supported by the French national funding scheme for clinical research (PHRC 2002 - HUS n°2898, "Étude anatomique et fonctionnelle dans la schizophrénie") and partly funded by France Life Imaging (grant ANR-11-INBS-0006). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.