The fiber g-ratio is the ratio of the inner to the outer diameter of the myelin sheath of a myelinated axon. It has a limited dynamic range in healthy white matter, as it is optimized for speed of signal conduction, cellular energetics, and spatial constraints. In vivo imaging of the g-ratio in health and disease would greatly increase our knowledge of the nervous system and our ability to diagnose, monitor, and treat disease. MRI based g-ratio imaging was first conceived in 2011, and expanded to be feasible in full brain with preliminary results in 2013. This manuscript reviews the growing g-ratio imaging literature and speculates on future applications. It details the methodology for imaging the g-ratio with MRI, and describes the known pitfalls and challenges in doing so.
@article{arxiv.1701.02760,
title = {Promise and pitfalls of g-ratio estimation with MRI},
author = {Jennifer S. W. Campbell and Ilana R. Leppert and Mathieu Boudreau and Sridar Narayanan and Tanguy Duval and Julien Cohen-Adad and G. Bruce Pike and Nikola Stikov},
journal= {arXiv preprint arXiv:1701.02760},
year = {2017}
}
Comments
This is the accepted version, accepted by NeuroImage. It contains minor revisions suggested by reviewers