The variability of MR axon radii estimates in the human white matter. Issue 7 (12th February 2021)

• Record Type: Journal Article
• Authors: Veraart, Jelle; Raven, Erika P.; Edwards, Luke J.; Weiskopf, Nikolaus; Jones, Derek K.
• Is Part Of: Human brain mapping. Volume 42:Issue 7(2021)
• Page Start: 2201
• Page End: 2213
• Publication Date: 2021-02-12
• Subjects: axon diameter -- diffusion MRI -- reproducibility -- variability; Brain mapping -- Periodicals; 611.81
• DOI: 10.1002/hbm.25359
• Languages: English
• ISSNs: 1065-9471

Abstract

Abstract: The noninvasive quantification of axonal morphology is an exciting avenue for gaining understanding of the function and structure of the central nervous system. Accurate non‐invasive mapping of micron‐sized axon radii using commonly applied neuroimaging techniques, that is, diffusion‐weighted MRI, has been bolstered by recent hardware developments, specifically MR gradient design. Here the whole brain characterization of the effective MR axon radius is presented and the inter‐ and intra‐scanner test–retest repeatability and reproducibility are evaluated to promote the further development of the effective MR axon radius as a neuroimaging biomarker. A coefficient‐of‐variability of approximately 10% in the voxelwise estimation of the effective MR radius is observed in the test–retest analysis, but it is shown that the performance can be improved fourfold using a customized along‐tract analysis. Abstract : We demonstrate a good to excellent reliability in the quantification of micron‐sized effective MR radii using in vivo human dMRI. As a result, we were able to observe the subtle inter‐ and along‐tract variability in major white matter bundles.