MRI‐based myelin water imaging: A technical review

Abstract

Multiexponential T 2 relaxation time measurement in the central nervous system shows a component that originates from water trapped between the lipid bilayers of myelin. This myelin water component is of significant interest as it provides a myelin-specific MRI signal of value in assessing myelin changes in cerebral white matter in vivo. In this article, the various acquisition and analysis strategies proposed to date for myelin water imaging are reviewed and research conducted into their validity and clinical applicability is presented. Comparisons between the imaging methods are made with a discussion regarding potential difficulties and model limitations.

Strategy‐based reasoning training modulates cortical thickness and resting‐state functional connectivity in adults with chronic traumatic brain injury

“…In particular, changes in oligodendrocytes, and subsequent myelination and myelin remodeling in the white matter are plausible candidate processes, as axonal connections are pivotal in the establishment of rsFC (Zhou et al., 2014). Further neuroimaging studies assessing white matter microstructure such as diffusion tensor imaging and myelin water imaging (Alonso‐Ortiz, Levesque, & Pike, 2015) may help to further clarify the validity of this hypothesis. Third, changes in the cerebrovasculature may be another mechanism.…”

New approach to phase correction in multi-echoT2relaxometry

“…For low-order polynomials the phase function can be accurately estimated at rather low SNR values. In particular, WELPE typically works at a much lower SNR than what is required for the application of multi-component T 2 estimation [6,25].…”

“…[1,2]. A standard approach to estimating T 2 is based on acquiring several images at different echo times using a spin echo sequence, and fitting one or several decaying exponentials to the magnitude data in each voxel individually [3][4][5][6]. A single exponential decay is often assumed [7][8][9], but in practice, the data usually consists of several decaying components [10].…”

The neurobiology of transition to psychosis

“…Quantitative MRI methods, such as T 1 -based inversion recovery, 96 are highly correlated with spatial 97 and age-related variations 98 in myelin content, can quantify both intracortical and white matter myelin, 99 and appear to be sensitive to even subtle dysmyelination. 100,101 Furthermore, T 1 -based methods are cross-validated with histological myelin staining 102 and postmortem myeloarchitecture 103 and show robust longitudinal reproducibility.…”